I feel it is very important to cycle your batteries at least every other month or so, I have found this is the best way to find out if you have a cell going bad. If a 600 ma flight pack is only giving you 350 ma after cycling it a few times, it is time to get a new pack. I read a few years back that 8 out of 10 crashes are battery related, that was good enough for me to not take them for granted, they do fail eventually.