These MacBook Air models can be identified externally by the 2393 and 2392 EMC numbers. Apple estimates that the 11-Inch "Late 2010" MacBook Air -- the MacBook Air "Core 2 Duo" 1.4 11-Inch -- provides an estimated five hours of battery life using its 35 watt-hour battery and the 13-Inch "Late 2010" MacBook Air -- the MacBook Air "Core 2 Duo" 1.
Battery: MacBook Air 11” 2015: MacBook Air 13” 2015: Size: 38 Wh lithium‑polymer battery: 54 Wh lithium‑polymer battery: Battery Life: Up to 9 hours of wireless web; Up to 10 hours of iTunes movie playback; Up to 30 days of standby time; Up to 12 hours wireless web; Up to 12 hours of iTunes movie playback; Up to 30 days standby time
Testing conducted by Apple in October 2020 using pre‑production MacBook Air systems with Apple M1 chip and 8-core GPU, configured with 8GB of RAM and 512GB SSD. The Apple TV app movie playback test measures battery life by playing back 1080p HD content with display brightness set to eight clicks from the bottom.
I have a mid-2012 Pro that i got in 2015 amd i read something similar. I keep it plugged in 90% of the time at least. The battery still Is pretty good when i use it unplugged. I just ordered a macbook air this evening, and I will probably keep it plugged in at home as well.0n07.