Anywhere between a few months and 8 or 9 years. Actually the ones that are more than about 6 years old have been recycled by now. I haven't kept track; with LiIon specialty batteries I put the date in service on them with a marker, but though I used to do that with AAs, the marker just wears off anyway so I don't bother anymore.

I have no idea how many times. Maybe some of them have been charged 120 times or so. I tend to have plenty of spares and cycle them rather than charging the same set over and over. Again, I started out trying to keep track, but the marks just wear off anyway, and I decided I didn't care that much.

The set that's in my Dinotte taillight right now I've decided to cycle hard just to see what happens. I run it about 90 minutes a day and charge it every 2 days. It's an old set that a friend gave me, saying they were junk. I found they were fine and she probably just had a cheap charger. But they're a bit old, only 2000 mAH. I've been running them for a couple of months now.