The battery on my still-otherwise-working 3rd gen iPod was totally dead. It's 20gb and to buy a new mp3 player of that storage capacity would have been really expensive, so I figured that for just $15 plus delivery, fixing it myself was a much better solution.
On opening the box I felt a little trepidation - I'm not a person usually considered "handy" and I was worried I'd got in over my head. But the printed words on the inside of the box reassured me "You got this" (a very nice touch, guys!) and I proceeded, very slowly, to follow the instructions and use the tools provided. It all went very smoothly and only took about 30 minutes from cracking open the box to charging the iPod with new battery on the charger. The only slightly fiddly bit was tucking the wires out of the way of the case when reattaching, but that just took patience and persistence.
Be slow and steady with the tools, exercise plenty of patience and set aside a good chunk of time so you don't feel rushed. It's worth it!