Enh... I've had several flip phones going back years. Samsung sch-3500, LG VX4400 and moto 550i, RAZR (GSM) and now the e815... None have had a problem with the flips. With the exception of the cingular phones, I've had all my phones for more than a year.

Candy bar phones on the other hand, I've had the original Sprint phone, Some crappy Nokia and a moto V120, and had issues with phantom dialing and scratched screens.

Unless you submit them to abnormal use don't worry about a flip phone. If you're unusally hard on a phone you'll probably destroy anything short of a moto brick.