I leave my charger plugged in to the socket but not actually turned on (Live in the UK, we have switches on the plug, turning off the switch is just like pulling it out of the socket) so have to crawl under my desk any time I need to charge the MacBook. It's kind of annoying crawling under the desk though so I'm thinking of leaving it on all the time (Not charging the Mac, just leaving the charger on) but I've always known it to be good practice to let chargers discharge before you unplug it all, so by just pulling the MagSafe off of the MacBook you're not letting it discharge and it'll damage it over time. I've also heard it still draws a small amount of energy. I don't know, maybe I'm being a bit pedantic here, why would it matter if it causes a slight bit of damage over time anyway? Just FYI this is a secondary machine (My iMac is my primary) so it spends most days in sleep mode in the case, the battery works really well and rarely needs charging.