I kind of enjoyed this videos, he seems to have found a service in demand and making a living on it. My main questions is where does he get his donor boards for parts exchange?
There are many "sins of the repairer" in the repair and service industry (not just electronics). Perks (if you like free parts), scams and cons are frequent and some of these guys are professional bullshit artists.
Customers often don't come back to pay for the repair.
A customer may be told it's an uneconomical repair and leave their device.
A customer may be told it's an uneconomical repair on a simple job and get sold a new device with an enticement of a discount. "Would you like a data transferal service with that as well?"
Customer may voluntarily leave parts for the store (recycling or they don't want their old part).
The device will be repaired and sold if possible or raided for parts.
Customers may be downgraded or parts removed without them knowing.
Customers may end up with "value added" repairs where extra faults are added to the bill.
Parts may be raided from a customers device and reused in another repair job.
Repairers could source the genuine part or quality equivalent. But many customers would not know the difference sadly. If the parts don't just walk in the front door, they could have been purchased cheap and inferior brands or secondhand components, wrecked or water damaged pcbs, or the wrong components and specs may even be used.
There is the "no-fix-fix" where nothing is done and it's just given back to the customer and billed.
There is the "if-it-works-leave-it fix" where a faulty part is removed and the customer is none the wiser and given the bill.
Faulty or junk bin parts are sometimes shown to the customer from another repair to justify the price or faults.
Service bulletins or parts recalls often have warranty provided free parts and labor supplied by the manufacturer. The repairer could claim these back from the manufacturer but still give the customer a bill. Charge when the device should have really been a warranty job, or charge when the sent the device to the manufacturer and did no work at all.
Vintage parts being unnecessarily removed (for resale) during a repair or restoration could leave the customer with a bill and the repairer some extra sales and then some nice parts to sell to another customer for top dollar.