I've seen a ton of guides for building units, many for winning battles, using resources and the suggested order for building structures. But nothing about units and exp.
I hope to remedy this now.
Exp really isn't that complicated, for every 3 exp a unit gets they gain an additional Hp or Damage point. Then, if they gain another 3 exp, they get a point for the other stat. Alternating every 3 exp.
So if you build a cavalry unit with the damage upgrade (Weapon doesn't matter) it will start with:
After recieving 12 exp it will look like this:
It doesn't matter if it gets Hp or Damage first, because it will ALWAYS be followed by the other stat.
Experienced units are also the last to get hurt in their group SO the order stuff gets hit is:
Meaning a armored infantry unit with 1,000,000 exp still gets killed before a range infantry unit with 0 exp.
However, a unit with 10 exp will be the last to die, if he has the most of exp of any unit of its EXACT makeup.
I've looked and tried to find exactly how exp is calculated, but everytime I think i've got it I put some numbers in and I get a different answer than I should.
So all I know is it has to do with the number of troops killed / the number troops still alive, (1-inf, 2-cav, 3-hvy) and some other calculation(s) that I can't pin down.
SO... *Short version*
1. Range units are better than Armor and Damage. Because no matter how much exp those units get they will never gain range, however range units can gain HP and damage.
2. Keep your units with Exp alive. They can become the diffrence in a close battle. Always keep a few units with little to no exp with your high exp units to die for them. Just like you have armor with range, keep some low exp with your high exp.
3. The closer the battles the more exp you get, but consider experience a bonus. Because the closer the battle the higher the losses. Meaning it's not a good idea to make battles intentionally close to gain more exp. because more units are a larger advantage than more exp. As it takes 108 exp. to equal the health and damage of one lost cavalry unit.
Feel free to add or dispute anything, as I don't claim to be an expert.