My faithtful old iPod Photo has trucked along as Family Jukebox for years, but the battery had become utterly shot. It wasn't a big deal, as we left it on the stereo dock, but leaving the dock off for too long netted a fully-discharged and complaining iPod.
Finally, the click wheel stopped working and I planned to chuck the beast. But a bit of Googling taught me that (1) replacing the battery was fairy easy and cheap, (2) replacing the click wheel was difficult but also cheap, and (3) the battery may actually be causing the click wheel issues (age-related swelling), so fixing #1 might trickle down to #2.
Repair was tricky but doable. The instructions were clear, but hampered by three things:
1. The iPod opening tool (the first one, used to separate plastic from metal) is too delicate for the task; it broke almost immediately. I chatted with another iPod-doctoring friend, and he laughed and said the same thing happened to him. So the second tool had to pull difficult double-duty.
2. The tabs were trickier to unlatch than expected; they aren't hard per se, but it is difficult to figure out how they want to unclip.
3. The original battery adhesive is (or was for me) extremely hard; I had to really work to get the old battery out. Probably age-related, but this would affect anyone at this point.
Try not to break the first spudger. Don't try to shortcut by threading out the battery wires without unscrewing the motherboard. Be careful. Have fun.