Monitoring Battery Life
To check on your laptop’s battery life, choose Ab from the Apple menu at top left of the menu bar, click on , and choose .
The status shows all sorts of useful things about the battery, including theount and .
By 300 full charges, your battery may be capable of only 80% of its original capacity. Time itself causes wear an tear also: after two years most batteries are not up to snuff, even if the recharge count is low.
You can use tools like Battery Health Monitor if you have further concerns.