Battery and keyboard are the dealbreakers.

Check the battery cycle count and keyboard for sticky keys—those are the two most common issues on used MacBook Airs.

On Apple Silicon models (M1 and later), the battery is glued in. Replacement costs $150–$250. Open System Settings > Battery > Battery Health and look for cycle count. Under 500 is ideal. Under 1,000 is fine if the price is right. Over 1,000? Budget for a replacement soon.

Keyboards are trickier. The butterfly keyboards on 2018 and 2019 Intel MacBook Airs are famous for failing—keys get sticky or stop working. Press every key, especially the space bar. If it feels off, walk away. Newer models (M1 and up) have scissor-switch keyboards that are much more reliable, but still test them.

Also check the screen for “staingate”—a coating peeling near the webcam or edges. It’s less common now, but it happens. Look for blotchy spots when the screen is off.

If those three things check out, a used MacBook Air is a solid buy.