: Test every single key for responsiveness. Be particularly cautious with models from 2016–2019 , which use the failure-prone "butterfly" keyboard.
: Bring a USB drive to ensure every port works; a dead port can signal deeper logic board issues or liquid damage. Test Wi-Fi and Bluetooth to ensure they connect instantly. tips for buying a used macbook
: 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. : Test every single key for responsiveness
: 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 Wi-Fi and Bluetooth to ensure they connect instantly