number always fails eventually, its a bigger drain on the economy (even if your egypt).
Also you have to remember the pop Limit. 300 max. numbers goal is to stay at that all the time. quality only has to stay at about half that to win. but he can still go higher! eventually in any battle quality would be victorious as quantity spent more and more on units.
thats why you should buy upgrades when you can.
armour upgrades are VERY good ones to buy for two reasons.
1- there cheaper than line upgrades.
2- they effect ALL human units not just all your infentry for example.
there main use is enemys who spam one kind of unit so for a small cost you can boost your pierce or hack to hold them off, or if your army has lots of units types as they will upgrade all of them.
however vs a balanced army of different units line upgrades tend to be a better buy.
However you should not put of buying line upgrades for armour upgrades. armour upgrades are baught as you age up, your economy should fund the gold and food and wood just as you age up.
Out Reach
The guy who writes the erotic fan fiction in Yeebaagoon's signature