The battery in my 3rd ten iPod lasted 20 minutes. It was try to fix it or use it as a paper weight.
The screen removal was the hardest by far. In the end the plastic frame and all the plastic tools were broken. The rest of it seemed to go smoothly but the iPod never came back on. it was probably the soldering. Too hot and you kill the logic board, too much solder and the connections cross and you kill the logic board, metal spudger touches too many things at once and kills the logic board.
I need to get a better soldering iron, and practice with it. iPhones with screws and ribbon cables are so much easier than this.