We just keep everything forever and repair it until it can't be repaired any more.
I have a cordless drill for example. Only 12V and 10+ years old. Replacement batteries are x2 for $25 on the web. When the direction button prevented it from working, I took it apart and repaired it. Was just a piece of plastic in the trigger assembly that was mis-behaving.
I repair my 52 year old electric lawn tractor when necessary. It hardly ever needs any attention. This winter I'll tear down the mower deck motors (x3) and clean the commutators and check the bearings and brushes. Parts are quite affordable if parts are needed. Also one of the reverse speeds is a bit flaky. I know from experience it just needs a $2 microswitch. And the transmission is leaking a little. That'll be a $10 shaft seal that needs replacement. Easy task. Good for another season come spring.
Do similar things with our cars. Younger teen's car needs a water pump. $150 for parts and we'll do the task over the weekend. ~2 hours according to several videos I've watched about the task. Teen asked why I didn't just take it to a shop and was horrified to hear what it might cost to have someone else do the work. Apparently shops charge 4 hours to do this task at $100+ per hour around here plus parts.
We both wear our clothes until they are no longer presentable - and then wear them more around the house. They are truly just rags when we give up on them. Same with furniture and other household goods.
The savings adds up. Pay attention to how often other people buy stuff. Sometimes seems like other people shop every week for clothing or household things or some other doo-dad.