If a laptop is going to be used via mains power most of the time, is it better to leave the battery in or out?

I run my laptop from mains powers most of the time and I always leave the battery in. I have read that you can extend the life of the battery by taking it out, but there is no universal agreement that this is in fact the case. With the battery in at least your computer won't go down during a power outage.

Thanks Budapest. I have heard varying views on this. Guess I will just leave it in