DIY it. Our dryer stopped heating, so I popped the screws off and it turns out the heating coil had burned out. Like $20 on Amazon. Our kitchen sink's faucet cracked and started leaking down the hose into the cabinet below so I bought a new one at Lowe's for like $20. Our oven stopped heating and the clock area where the control circuit is located kept clicking so I gave it a good smack like the primate I am. Free.
Too bad the heating coil wasn’t DRM paired with the dryer, forcing you to have to contact an official repair shop, we could have gouged you for way more than $20.
The examples you gave are much lower in scope than replacing an HVAC.... At various times I have done all of your examples. I do not dare to replace my home's HVAC system.
