i've read that people reinstall OSX so as to get rid of all the preinstalled crap. does it free up lots of space? does it cause any problems? also, what should i do battery-wise? run it until it drains, then charge it while its on or off? or charge it all the way up first, then drain it, then charge while its on or off? and do i leave it plugged in all the time, or let it run down, then charge, then run down, then charge constantly? is it bad to just have it plugged in all the time? this will be my first mac, and my first laptop. i know the basics to OSX, but aside from that, i'll have some readjusting to do. is there anything i should know about settings, keyboard commands, etc? hope that's not too vague... thanks guys!