“If you thinks its expensive hiring a professional, wait until you try an amateur!” Rings true with a couple of recent jobs:

iMac 27” brought in after somebody offered the client a cheap HD replacement…. my cost to diagnose & fix was over £400 to replace the logic board that was shorted as a result of not working in a static protected environment.

An iPad came in a few weeks ago, not working after having a new screen fitted at a pc repair shop locally. Having paid them for the repair that failed it took us a week to source the components that were missing internally & get the iPad running properly.