I just got the apple bluetooth keyboard and mouse which I use with my pb/display. Should I shut them "off" with the switch when I'm not going to be using them, like at night, to avoid running out the batteries? Also, I might as well ask, I almost never shut down my PB (or any computer for that matter) when I'm done using it, I just close the lid or leave it and let it go to sleep. Keep in mind I use it often. Is there any harm in doing this?