I have read articles that are on both sides of the fence. One stated that when you first purchase your laptop to fully charge the battery then unplug it and use your laptop until the battery drains it's entire charge, then plug it back it in and leave it alone for at least 16 hours. Supposedly this extends the life of your battery. Honestly I'm not sure with all the laptops I've owned I have only had one battery totally quit on me. Others state if you leave your laptop plugged in all the time to remove the battery, but I am not a big fan of leaving the bottom exposed.
When I am at home and on my laptop I plug it in with the battery still in and have never ran into an issue. Now if your on the go use your battery for what it was meant for and just bring the power cord with you when you are running low on power. What I wouldn't suggest doing is leaving your laptop up and running all the time like a standard desktop computer. This most likely will degrade the life of your laptop and battery.