I only turn mine off after a windows update. I'm actually scared to turn off my computer. A few years ago I had a Dell that pretty much died when I shut it off and restarted it. I ended up spending an unbelievable amount of time trying to get it fixed before giving up and getting a new one. It was probably a fluke, but I still feel like one of these days my computer is going to shut down and never wake up again.
Dell is a horrible company and their products are shit. The laptop I owned broke down in less than a year after I purchased the thing and they would not replace it, so I bought a Vaio.