I've always been very careful with my lipos also. I've never over/under-charged, never over-amped, and always balance charged them. (Eh, I guess I did leave a couple of cheap eBay ones alone for too long and they lost their ability to hold any real capacity.)

Even with good care though, I've had a couple of maxamps cells swell on me recently so I had to put them down for the saltwater nap.

Mostly I've had good luck though.