We had this discussion a few months ago.  I will
summarize some of the points.

1.  Your friend is correct.  The contributors who
mentioned wear and tear on hard drives and
power supplies are also correct, but the cpu
and motherboard tend to be more expensive
to replace.  (Monitors may be a problem, too.)

2.  Many servers are never turned off, as has
been mentioned.

3.  Outside of monitor life-span, the most serious
risk from leaving a computer on all the time is
from electric surges, especially during storms.
A surge supressor and lightning arrestor can
help to minimize that risk.  Even leaving a
computer plugged in can result in problems
from storms.  (I suspect that is more true now
with ATX power.)

Conclusions: leave your pc on while you intend
to use it (for the day), but turn it off when you are
done for the day.  Unplug it if you are going away
for a while and/or if stormy weather is predicted.
If you are really conservative, unplug it always.
If you have deep enough pockets, get a UPS,
which will have some isolation built-in.

Dean Kukral
Dept. of Mathematics and Statistics
Wichita State University
[log in to unmask]

-----Original Message-----
From: Errol <[log in to unmask]>
Subject: [PCBUILD] Computer always on ?


>Hello Everybody,
>
>A friend of mine never switches his computer off.
>
>He says that the act of switching a computer on every day
>gives the machine a big "shock" and shortens the life of a
>computer.
>
>What do you folks think about this theory ?
>
>All the best,
>
>Errol Lishman
>Johannesburg
>South Africa