I just got my first Mac, a MacBook Air and everything is just great but my brother told me to leave my Mac plugged in at 100% and never unplug unless I want to take it out. Is this bad? I was running my Mac purely on battery for the past week and charging it when it drops to about 5%? So now I dunno what to do now. Should I keep my Mac plugged in or run it down and charge it up? I also tend to use my Mac on my bed, is this bad? I see my CPU average temp go to about 50 degrees but when I start playing HD videos and flash games it goes to about 80 and the fans are not kicking in with just 2002 RPM for few minutes. Oh and I always wondered why does this happen ,for some reason the CPU temp just spikes to about 85 degrees and remain till the fans kick in or I lift it away from the bed for a few minutes. Anyone can explain this? Should I start using my Mac on a hard surface? Does heat ruin the battery?