I balance every time. I've even balanced packs for those who claimed to never balance before. Surprisingly, they're usually fairly balanced (maybe a tenth or 2 off).

Balancing won't hurt them, neither will charging them unbalanced. Worst thing you can do to a LiPo is run it low. I usually break my packs in pretty easy (no more than 8min for the first 4 charges or so), and I NEVER run to cutoff. After 1-1.5 years or so, you can start to feel the punch fade in a main though.