There's a lot of information about that if you keep a Laptop battery
charged between only 80% full and only 40% full, it will be servicable
over the years for four times as long.

Other information I find says it is the charging and discharging that
wears the battery out.

The laptop i have (with a built in battery) is mainly used in one room,
so it is easy to keep it plugged in *all the time* to mains electricity.

Would it be better to prolong the life of the battery to keep it plugged
in all the time or to go for the 80% - 40% option. Thanks.