Is it bad to leave your laptop plugged in all the time?
It won’t make any difference. Your battery doesn’t infinitely charge; the circuitry in the battery stops excess charging automatically once it reaches capacity. After this time, you can leave the laptop plugged in for as long as you wish.
It is of course more power efficient, and will get better performance, to run on mains power rather than continually discharge and recharge the battery.
Thanks, nice to know it won’t harm my Minibook!