Age of History 3: Legacy upgrades tier list

What the tiers mean:
A: Get this upgrade as soon as possible
B: Great upgrade, you should get this
C: Good upgrade, maybe get this
D: Ok upgrade
E: Bad upgrade, it helps but it’s not worth it
F: Don’t get this upgrade

Here’s my thoughts on which upgrades you should get first and why.
The game just came out, so I’m probably wrong on some aspects. I might come back later and update this guide if I change my mind on stuff.

Please, do discuss your thoughts in the comments, I’d love to read them.

Construction Cost: -2.5% / -5% / -7.5%
Construction Time: -5% / -10% / -15%

This is E tier. You should never choose this, unless somehow you’re super rich and you want to mass build buildings.

This is really not useful at all, construction is already not worth it anyways. You usually have several years of waiting between wars, so whether your building is ready on september or on october has very little impact. And say you want to buy a farm, it costs 135 gold. These upgrades lower its cost to 131/128/124. Spending all these legacy points just to potentially save ~10 gold per building, very bad idea.

Tax Efficiency: +1.8% / +3.6% / +5.8%
Increase Tax Efficiency Cost: -2.5% / -5% / -7.5%

This is E tier. Only get this upgrade if you have lots of provinces with 150k+ population.

Let’s better understand how good taxation is.
Here’s the formula given for the income from taxation: 0.001+(min(Population,150000)÷27500)×TaxEfficiency%
First, notice that any population size over 150k is treated like a population of 150k.
Say all your provinces had the maximum 150k population. And say the typical tax efficiency in a province is somewhere around 10%. Then the income from taxation will be about 0.5464.
So if you have 20 provinces multiply that by 20 and you have an income of 10.928 gold.
Now if you get the upgrades, your tax efficiency in each province will become 0.6446 / 0.7428 / 0.8628, so with 20 provinces, you’ll now generate 12.9 / 14.9 / 17.3 gold from taxes. Each upgrade gives a rough +2 gold per month! That’s not bad for a 20 province country.

Now clearly this upgrade gets better the more provinces your have. If you only have a few provinces, then the bonus income will be nothing. And if you have lots of provinces, then you’re probably already doing great. So in my mind, this upgrade is not very useful.

Province Maintenance: -3% / -6% / -10%
Develop Infrastructure Cost: -2.5% / -5% / -7.5%
Maximum Level of the Supreme Court: – / +1 / +2
Maximum Infrastructure Level: +1 / +2 / +2

This is D tier. Get this upgrade when you’re already snowballing to help you snowball even faster.

The infrastructure stuff doesn’t do much at all, you still have to buy the infrastructure and most of the time you never reach the maximum infrastructure anyway.
Better supreme court is nice. Reducing the corruption is a great source of income for larger nations. The more provinces you have, the more extra income you get.
Province maintenance is a good source of income afaik, but again, it’s better when you have lots of provinces, in which case you’re already snowballing.

Manpower Recovery Speed: +2.5% / +5% / +7.5%
Maximum Manpower: +5000 / +10000 / +15000
Battle Width: +4 / +6 / +8

This is F tier. There’s no reason to get this ever.

Manpower recovery is useless. In war, either you win the battle and destroy most of the other army in the process, or you lose the battle and most of your army. Manpower recovery will not help you win the battle. If you lose a battle, the enemy will then take all your provinces, and manpower recovery might get your army back to its full size, but uhhh if you lost the first battle why would you win the 2nd battle?
Maximum manpower is useless, you never reach 0 manpower even with the maximum regiments recruited.
Battle width doesn’t matter. The default is 20. That means by default you can make an army with 20 second line regiments and 20+ first line regiments, for an army of 40+ regiments. By the point you’re actually able to build a 40+ regiment army, you will already have found other bonuses to increase your battle width, with technology and other things that I forgot. The battle width is capped at 40, and the game gives enough bonuses to reach that cap without buying this upgrade at all.

Research: +3% / +6% / +10%
Research per Month: +4 / +8 / +12

This is F tier. There’s no reason to get this ever.

Yes, research is really useful. Having very fast research can give you access to stronger units and much more. But, there is a “maximum research” limit, limiting you in how fast you can research. And most of the time, with just one library (or just a bunch of unrelated bonuses) you reach that limit. Reaching the research limit is really easy, what’s difficult is increasing the limit. It can only be done by increasing the capital city’s growth rate and by leveling up the capital city. Don’t buy this upgrade, just build (or conquer!) a library instead. By the way, once you reach the maximum research, you should go in the budget tab and reduce the research spendings to gain a nice extra income.

Growth Rate: +3% / +6% / +10%
Increase Growth Rate Cost: -2.5% / -5% / -7.5%
Additional Buildings in Province: +1 / +2 / +3

This is D tier. Only get this when you’re snowballing to further snowball.

The additional buildings don’t matter ever, and increasing the growth rate manually is only useful for increasing the maximum research, so the only interesting thing this upgrade gives is extra growth rate.
Simply put, growth rate gives you local manpower, which gives you a bigger regiment size limit.
Having more population can give more taxation income, but it’s not worth it.
More importantly, growth rate affects the maximum economy in a province. Because investing in economy is the best way to increase your income, you’ll want to buy this legacy upgrade so that you can get more economy and more income. Like, say you have a bunch of low growth provinces and you hit their maximum economy. So now you’re forced to invest in the economy of the bigger provinces, which is more expensive and less profitable over time. After you buy this upgrade, now you can go back to investing in the small provinces again until you hit their max.
So this upgrade can be useful when you have many provinces and you want to grow the economy more and more.

Income Production: +2% / +4% / +6%
Production Efficiency: +3% / +6% / +10%

This is D tier. Get this only if you’re already making very good money with your resources.

It’s just a money boost for your resources. The income varies greatly from one resource to another, so this is more worth it if you have more valuable resources. And just like most economic upgrades, this upgrade gets better the more provinces you have. Don’t choose economic upgrades if you have more fingers in your hand than you have provinces. Also, the income you make from resources depends directly on the province’s economy, so really, you should be investing in the province economy as a priority.

Maximum amount of Gold: +10% / +20% / +35%
Invest in Economy Cost: -2.5% / -5% / -7.5%
Advisor Cost: -10% / -20% / -30%

This is E tier. Only get this once you’re already rich and you want to mass invest in economy.

The advisor cost decrease is laughable. One advisor only costs around 30 gold, so you will save 3 / 6 / 9 gold per advisor. And you buy new advisors like once every 30 years…
The maximum amount of gold increase is even more laughable. The default is already in the thousands, and why would you ever stockpile thousands of money?!
The only bonus worth looking at here is the Invest in Economy Cost. Investing in economy is the best way to increase your income as far as I know. So this helps you with that, but not by a lot.
Say it cost you 20.0 gold to invest in a province’s economy. Then, with this upgrade, it will instead cost you 19.5 / 19.0 / 18.5 gold. This looks small, but if you’re investing 5 times in 50 provinces, then with the -7.5% reduction you would save 375+ gold. It can potentially be worth it if you really want to get tons of money.

Generals Attack: +1 / +1 / +2
Generals Defense: – / +1 / +2
All characters’ Life Expectancy: +3 years / +6 years / +10 years
Maximum Level of the Military Academy for Generals: +1 / +2 / +3

This is B tier. Very good option, get this a bit later on to gain a small edge in battles.

In this game, improving your army is your #1 priority. If you lose a battle, you will lose the war and your lands. This upgrade will give you a minor boost to your army’s stats to make sure you win.
I do not know yet if attack or defense is better, but I know that they’re essential. In a battle between two armies of equal size, you will always win if you have more attack / defense.
The increase in life expectancy actually harms you, in my opinion. Because your old general will take more time to die, meaning you’ll have to wait longer to get a new general that has the new improved stats. I had a game where my very old general had like 9atk 9def and when he died the next one I recruited had like 13atk 13def. Make sure to recruit new generals!
And the maximum level of the academy only matters later on when you have tons of money and you’re snowballing. Again, it gives essential army boosts that can even make you win battles where you’re outnumbered.

Units Defense: +1 / +2 / +4
Max Morale: +5% / +10% / +15%
Maximum Level of the Military Academy: +1 / +2 / +3

This is B tier. Great option, especially get this once you have the money to upgrade the military academy.

Extra unit defense is helpful, especially in the early game where you’re at risk of being attacked by bigger powers. Max morale I don’t know what it does exactly but you should always take anything that helps your army.
The best thing about this upgrade is the military academy max level. In case you didn’t know, the Military Academy is overpowered. Each level up gives +2 attack and +2 defense to ALL YOUR UNITS, and lets you have 8 more regiments. You buy the level ups as soon as possible, and then you build a bigger & stronger army, and then you can just invade all your neighbors and you’ll always win because you have more stats and more regiments.

Discipline: +5% / +10% / +15%
Units Attack: +1 / +3 / +5
Devastation: +10% / +15% / +25%

This is A tier. Get this as soon as possible.

Discipline increases your effectiveness in battles, you always want to get as much discipline as possible so that you win your battles. This stat is actually really really important I think.
And the extra unit attack, again, this makes you win battles and that’s the only thing that matters in this game.
The devastation bonus isn’t very useful, from my experience. You don’t really notice when you gain loot, so it’s hard to tell how good it is, but I’d say your income shouldn’t depend on loot since wars give you aggressive expansion and war weariness.

Regiments Limit: +10 / +20 / +40
Siege Effectiveness: +10% / +20% / +30%
Recruitment Time: -5% / -10% / -15%
Army Movement Speed: +5% / +10% / +20%

This is A+ tier. It’s overpowered. There is no reason to not choose this.

This upgrade gives you +40 regiment limit. FORTY in all caps. In the early game, when you only have around 10 regiment limit, you’re at risk of being invaded by a stronger power, or by an alliance of countries. Typically, countries pair up together in alliances and fight each other two against two. If you increase your army size by just 10, it’s as if you have the army of two countries! Now whenever you fight a war it’s more like a 3v2. And if you have +20 regiment limit then you’re fighting like it’s a 4v2. It’s stupidly overpowered. You don’t even need an alliance at that point.
The other bonuses aren’t very good. Faster recruitment won’t help you at all. Faster speed & siege could potentially help you conquer a large country faster, but it’s not going to help you win the battles.

Improve Relations: +10% / +20% / +30%
Diplomacy Points: +15% / +35% / +50%
Loan Interest: -5% / -10% / -20%
Maximum number of Loans: +1 / +2 / +3
Maximum Level of Capital City: +1 / +2 / +3

This is C tier. This will help you in many aspects.

The buffs to Improve Relations and Diplomacy Points are worthless, what you already have is enough.
The loan bonuses are interesting. I’ve never tried using loans, but, I wouldn’t be surprised if this helps you get your economy going. Like, you get a loan, you use it to invest in economy, and then the loans pay themselves with the extra income. Especially with bigger maximum of loans.
But the bonus here that I think is very useful is the capital city max level. Leveling up the capital city gives you more income directly and through reduced province maintenance cost, which in itself isn’t that good, but it also gives you a very valuable bonus: increased maximum research limit. In this game, increasing your research is really easy, but it quickly caps at a maximum. Increasing the maximum is the true way to research faster, and researching faster is important. The most important thing to research is new army units, for their improved stats. Then there’s laws, buildings, and miscellaneous bonuses. Finally, there is the “advantages” system where you can spend advantage points on the bonus of your choice. You get advantage points by getting research done. These advantage points can get you very very good bonuses, like regiment limit increase.

Loot: +10% / +20% / +30%
Income from Vassals: +5% / +10% / +15%
General Cost: -5% / -15% / -25%

This is F tier. There is no reason to get this ever.

Loot is never worth it. You won’t even notice that you gained loot, and you don’t want to depend on loot as a source of income, because you’d need to be at war a lot which means war weariness, aggressive expansion, etc.
Income from vassals is negligible too, especially considering how bad it is to have vassals in this game. Vassalizing a country costs you aggressive expansion anyway, so you might as well annex them and get full control over the provinces. (Unless you enabled “call vassals to war”!)
General cost, yep, little to no effect. You’ll recruit a general once every 40 years, it’ll cost you 30 gold, yeah, decreasing the cost to 23 is never worth it.

Maximum Number of Alliances: – / – / +1
Maximum Advisor Skill Level: +1 / +1 / +2
Advisor Pool: +1 / +1 / +2

This is E tier. Choosing this upgrade is usually a gamble with limited benefits.

The extra alliance is not as good as you think it is. Having an alliance is essential in the early game, to defend yourself from attackers. But as the game progresses, you become stronger to the point where you can attack and defend on your own. By the time you have enough legacy points to get the extra alliance, you won’t need an extra alliance.
The extra advisor skill level can be good. If you have an advisor that gives +1 unit attack, then you can level it up further to get more and more unit attack. There are a few advisor bonuses that are good to level up, but they don’t always show up, and it costs gold for each level up.
The bigger advisor pool helps a bit with this but otherwise it doesn’t do much.

Manpower recovery from a disbanded Army: +25% / +50% / +75%
Aggressive Expansion: -5% / -10% / -15%
Diseases Death Rate: -10% / -20% / -30%

This is E tier. It lets you expand a tiny bit faster, but it’s not worth it.

The manpower recovery from a disbanded army is a joke, why would you disband your army? In this game, you need to have the strongest army possible at all times.
Deaths from disease make little to no impact on anything. It might reduce your population a bit which in turn might reduce the taxation income a little bit, but you won’t notice.
The aggression expansion is the thing we care about here. Note that this doesn’t help you reduce aggro faster, what it does is it makes you gain less aggro when performing certain actions. So with this, you might be able to take a few more provinces without reaching the 100 aggro limit. It’s not really worth it in my opinion, but yes, in theory this lets you expand faster. When you want to conquer tons of stuff in the endgame, you don’t need this upgrade because your army is now so strong that you can just ignore the aggro limit and crush coalitions.