If you are the one buying a used Mac from a third party, experts on Reddit and Medium suggest these checks: 5 Things to check before buying second hand Macbook
: Manually sign out of iCloud , iMessage , and Apple Music/iTunes . we buy macs
: Use the "Erase All Content and Settings" feature (available on Macs with Apple silicon or the T2 Security Chip running macOS Monterey or later) to factory reset the device. Tips for Buying a Used Mac If you are the one buying a used
: Apple Trade In allows you to swap your device for credit toward a new purchase or an Apple Gift Card. If it has no value, they will recycle it for free. If it has no value, they will recycle it for free
: Optionally unpair devices like keyboards or mice if you are keeping them.
: Sites like SellYourMac.com specialize in purchasing used Apple gear. They typically buy devices less than 10 years old, as value tends to drop toward zero after that point.
: Large retailers like Best Buy also offer trade-in programs where you can receive store credit. Essential Pre-Sale Checklist