Replace your MacBook Air battery when it starts swelling or dying fast.

You’ll know. The telltale signs are pretty obvious once you know what to look for.

The biggest red flag is swelling — if the trackpad feels clicky or uneven, or the case is bulging, stop using it immediately and get the battery replaced. That’s a fire risk. Next is runtime: if you’re charging twice a day for light use, or the laptop shuts down at 20% battery, it’s done. Check System Report → Power → Cycle Count. Apple says 1000 cycles for modern Airs, but I’d start thinking about a swap once you’re past 500 and noticing degradation. Also, if “Service Recommended” shows up in the battery menu, that’s not a suggestion — it’s a ticket.

Don’t wait for it to completely die. A weak battery can also slow down your CPU (throttling) as the system tries to protect itself. Replace it for about $130-$200 from Apple or a good repair shop. Third-party batteries are cheaper but hit-or-miss — I’d stick with Apple for this one.

Future You will thank you when the laptop doesn’t die mid-meeting.