Supposedly the smaller Li-On batteries found in those small tail lights cannot be charged for 1,000 times, my understanding their about 500 times. But just to make sure I sent an E-mail to Cygolite with that question, I will share their answer when I hear back.

Front lights use larger batteries, those could probably do 1000 cycles. Almost all rechargeable lights use a proprietary system, Cygolite ExpiliOn is a user replaceable battery that you can order from Cygollite. The Phillip Saferide uses 4AA rechargeable batteries instead so you don't have to order an expensive proprietary battery from the manufacture.