how low to let MacBook air go before charging

oldipad718 wrote:

how low should my MacBook air battery go before charging?

Leave it plugged in and charging whenever convenient to do so. Leaving the computer plugged in will not damage the computer or the battery. The MacOS manages the charging/power system very well. There is no need for you to micromanage it.

Do not, however, let the Mac drain low on a regular basis. Doing so can shorten the life of the battery. For Apple's tips on managing your battery, see:

Batteries - Maximizing Performance - Apple

Regards.