: Expect reduced runtime; 1,000 is typically the limit where Apple recommends replacement.
: Open a full-screen white background to check for dead pixels, lines, or spots. For newer models, verify if True Tone is available in Settings; if it's missing, the screen has likely been replaced with an inferior third-party part.
: Test every single key for responsiveness. Be particularly cautious with models from 2016–2019 , which use the failure-prone "butterfly" keyboard.
Before handing over any money, perform these physical and functional checks:
: Go to Apple Menu > System Settings > General > About > System Report > Power . Under 300 cycles : Excellent condition.
: Use a tool like DriveDx to check the total data written (TBW). If the SSD is heavily worn, the entire machine is at risk since storage is soldered to the board on modern Macs.