@frase Just wait until you start getting in 2016-2020 MacBook Pro's. Those things SUCK! Everything is soldered onto the logic board, including the SSD and to make matters worse, the built-in SSD is encrypted AND protected by the T2 security chip. You'd better pray to whatever computer god you believe in that they remember their password and that their logic board works and doesn't have any bad ports otherwise you can't even get into Target Disk Mode to transfer the data. To make things even worse, you have to use this expensive crappy 1 foot cable from Apple, which only works if you connect it to a newer Mac in order to enter Target Disk Mode to copy the data. The connector is thin and crappy, and will disconnect at the slightest touch, possibly corrupting their data in the process.
Basically, Apple has done everything in their power to make a disposable paper bag that you have to pay an iCloud subscription for so you won't lose all your data if the computer goes down. The liability of working on modern Macs makes working on them a very unattractive prospect, especially since there really aren't any replaceable components. Even the freaking battery is glued in. When it comes to modern Macs, the only service you can really offer is data transfer or an OS reinstall, and the chances of mucking something up during a data transfer is much higher than a normal computer.
