If you can solder I’d say most mice are easily fixable. The most common defect for mice are the switches, which are usually quite simple to desolder, as there aren’t any components near them.

E.g. I don’t have much experience soldering and it took me under an hour replacing both switches on the G Pro Wireless as well as the battery. I’ve bought this mouse used about 5 years ago and I wouldn’t be surprised if it lasted another 5 years.