You can leave it plugged it. When it's done charging, the magsafe will change from amber to green and run off AC power. Just remember if you're leaving it plugged in for a long time, calibrate the battery once a month.
a bit off topic but when the battery is fully charged can I unplug the magsafe after i shut down the macbook but then plug it back in before I turn on the macbook, i assume the magsafe would display a green light as it will not charge the battery as long as its above 95%. I don't want to keep it plugged in when not using the macbook.
u still cant over charge the battery even when ur running in boot camp with windows?