I have some 3 cell LiPo batteries that I bought for some of my RC Airplanes in 2008 and they are still working well after yearly use, well enough that I use them for a shorter "warm up" flight before using my newer batteries. The best 2 pieces of advice I can give about LiPo battery care is 1) Always wait until they are completely cool before charging them again, and 2) Never let them sit on the shelf overnight fully charged. If even one cell dies, just like modbuilder says, it's not worth the risk of flying it.