Is it a good idea to keep laptop constantly connected to the internet (Yahoo mail for instance). Is it a better idea to turn off the computer and/or put it to sleep overnight or when not in use during the day? It's strictly a matter of personal choice. There are two schools of thought regarding whether or not to leave computers on constantly. On the one hand, the biggest "shock" to the electronic components in the computer is when it is powered on. On the other hand, leaving the computer on constantly may cause the hd's life to be shortened. If you do decide to leave it on all the TIME, just set the hd and display to power down after a defined PERIOD of inactivity. It will still retrieve your email, but the lcd will remain off and the hd will only spin if and when needed. Personally, I turn my systems off at night and have always done so.

Of course, either way you should have a GOOD anti virus utility resident at all times - especially when your system is online.I've read SEVERAL articles and studies on this subject and frankly none of the have really convinced me that one way or the other is right.

One of the BEST documented studies on power useage and energy costs I've read was done on incandescent and florescent light bulbs and there are proably some similarity to computer useage. If an incandescent light was repeatedly turned on and off, it shortened the life of the bulb by a wide margin because of the shock of the initial electrical pulse.

If I remember right the crossover point was 4 hours for an incandescent bulb and 8 hours for a florescent bulb for the savings in energy to offset the wear and tear and the cost of the bulb.

Personally, I leave my computer on 24/7 for my convenience.