MacBook Pro Charging & Battery Health

The primary reason why battery health drops is discharging and charging. Leaving it plugged in will power it most of the time where the battery isn’t used. It also won’t overcharge, as the charging circuitry will shut off charging at a certain point and only top off briefly when the charge level drops (mostly as a result of self discharge, but also providing supplemental power).

There are some recommendations to at least periodically use a device off of battery power.

AlwaysReady-00 wrote:

Should I keep my MacBook Pro plugged in all the time when I am using it?

Yes.

This is how you extend the working life of your battery—

If you are near the mains leave it plugged in, if you need the portability then run on battery only.

The built in software manages the battery health for you.

About battery health management in Mac notebooks

About battery health management in Mac notebooks - Apple Support