Fixing things, maybe a bit beyond the typical DIYer because I'll even do things that don't exactly make sense. Stage 1 I would say is that you diagnose and replace entire major components yourself. Stage 2 is you diagnose further and replace subcomponents. Stage 3 is you start replacing the smallest failed component on a subcomponent (replacing the capacitor on a small sub board on a larger device)
I'm at stage 2.
If the alternator on my car gives out, I'll figure out which component failed (brushes? voltage control module?) and I'll replace or fix it.
If my washer acts up, I'll basically fix whatever it is.
My dad's cement mixer stops working ? Take it apart and notice the pulley driving the drum is loose because the set pin came undone.
Basically I'm acting like the typical person outside of cities just a generation or two ago.
The best part is, once you fix something once, you learn about it and then you really don't want to throw the device away when the next thing breaks because you feel like you already know and understand it a bit so might as well keep going.
It doesn't always make sense once you factor in your time, but that applies to many hobbies. Atleast this one technically saves you money instead of costs you money.
Tldr; fixing mechanical things is a bit like debugging and troubleshooting, but instead of just fixing some code that annoyed someone somewhere, I'm fixing things I use everyday.