I'm about to buy a Samsung Galaxy Ace (it's not much expensive and I think it's a pretty good phone), however everyone has been complaining with the battery life but admitting that isn't bad compared to all the other smartphones.

I read about how to save battery with tips/tricks, and I'll certainly do it; but I'd like to know whether a battery life would increase recharging it only when completely empty (some old phones used to gain life expectancy from that, I don't know if things are changed now)