The trackpad can be replaced without removing the battery.

The processor, RAM, and flash memory are soldered to the logic board. Repairs and upgrades will be impractical at best.

The top case assembly, which includes the keyboard, battery, and speakers, is firmly glued in place—making all those components hard to replace separately.

The Touch ID sensor doubles as the power switch, and is paired with the T2 chip on the logic board. Fixing a broken power switch may require help from Apple, or a new logic board.