I am using M3 Air but its giving me battery timing of merely 11:30 hrs on normal usage with 50-60% brightness which is even lower than M2, I contacted Apple support and they said that use it for nearly one month and issue will be solved. So does battery timing will get improved if I use it for one month.
MacBook Air 13″, macOS 15.3
I would follow the guidance of the Apple support staff and see.
Meanwhile, here is some additional guidance from Apple on the subject of battery care:
Batteries - Maximizing Performance - Apple Support
About battery health management in Mac laptops - Apple Support
There are many notes regarding battery life, comparing those two specific models and others: MacBook Air 13-inch and MacBook Air 15-inch - Apple. They are tested using very specific conditions including but not limited to display brightness.
From my observations Apple's claimed battery life is conservative. In other words I get considerably more than they claim, but Apple's "eight clicks from the bottom" setting is much too bright for me.
Definitely explore the links D.I. Johnson posted, and follow Apple's guidance.
Less Battery Timing of New M3 Air
