My iPod 4G was seven years old with the original battery. I thought it was a good time to install a fresh one although the original battery still held a charge. I use this iPod on my motorcycle for musical entertainment and wanted to ensure that it would continue on with me for many more trips. I like this model because it has the external jack on top so that charging it and using a remote with it is easier.
Opening the case of a seven year old unit that had traveled close to 100,000 miles in dusty road conditions while on a motorcycle took a bit of effort. After opening the case changing the battery took a few minutes following the instructions. I made the battery wiring placement easier by removing one tiny screw holding down the mini plug board thus allowing the wire to be placed easily under this board. I had to carefully peel the original battery from the case as it was held down by some sort of adhesive. I used the included tools and also the ifixit Sesamo tool to open the case.
Take your time and work carefully to minimize scratching the plastic upper case. The plastic tools can be dulled so I used the Sesamo to begin the process.