For Apple, I buy used parts in the hope that they come from a genuine device being parted out on eBay each for 50% of the cost of the original device because I know all the new parts are not just fake but bad fakes. I get a part that is past its expiration date, rather abused, but will work. I soak the MacBook in corrosive chemical baths to get the industrial super-strength glue (thank God it’s not epoxy?) to loosen up a little before I get out my exacto, needle nose pliers, a scraper, and a plastic pry tool. I pray nothing breaks while I try to get the part out. Something inevitably breaks (also, try to avoid piercing a battery while you pry it out; li-ion batteries do not like to be manhandled). The cost of a replacement part does not make economic sense. I either let the product sit disused on a shelf hoping to find the part cheaper at a later date, hock the device on eBay for pennies on the dollar for a parts shark to snap up then part out, or throw it in the trash because I’d rather not sell my eight hundred dollar phone for a hundred dollars and this at least gives me the satisfaction of cursing at Apple while I do it.
(Yes, the Apple story is an amalgam of many different adventures with different endings over a decade with many different devices, the majority of which were either ultimately written off or else repaired at prices that didn’t make much sense.)
Oh, in addition to sometimes doing my own repairs, I’m also the final arbiter when it comes to all IT purchases for a school. When I’m asked if we can/should get a fleet of Macs for the faculty and students, I insist we get Thinkpads or Latitudes instead.