response 1 of 20:

Apr 8 04:11 UTC 1994

        I have no idea what the technical ramifications are, but my
computer hasn't been off for more than a few hours since early January. 
The times when it has been off for brief periods of time have either been
when I was doing hardware work or during thunder storms, and the time in
late December and early January when it was off was because I was out of
town for a week.  Part of it is because I've heard it's better for it to
be left on, but it's mostly because I don't want to wait the 30 or 40
seconds it takes it to boot.

response 3 of 20:

Apr 8 11:50 UTC 1994

Turning things off and on does stress the components.  Ten or fifteen
years ago this was a serious concern.  Minicomputers  had quite a lot
of parts and those parts weren't as high-quality as electronic parts
are today.

Today, however, there are fewer parts because the level of integration
in today's ICs is so much higher.  The parts are much better, too.
A lot of research has gone into discovering how ICs fail and how
to design and build them so they don't fail.  The result is parts
that stand up to the stresses of power-cycling better than ever.

My educated opinion is that as long as you're not turning the power
on and off several times an hour you're probably not risking
early failure.

response 5 of 20:

Sep 26 22:41 UTC 2000

I've wondered about this.  Not with respect to my PC, which I suspect
doesn't care, but for my stereo equipment.  My amp is a Fisher 400, which is
from the vacuum tube era.  Each time I switch it on, there's a sizable
current pulse that goes through the cold tube filaments.  (This is part of
the reason light bulbs tend to burn out when first switched on.) This
stresses both the filaments and the power supply.  On the other hand,
leaving it on uses up some of the life of the tubes.  My compromise is to
leave it on if I'll be turning it on again within an hour or so.  Otherwise
I shut it off.

response 7 of 20:

Sep 26 23:27 UTC 2000

In fact, the linear, all triode, push-pull audio amplifier I designed and
built in college had its filaments on permanently.

response 9 of 20:

Oct 18 12:22 UTC 2000

I'm one of  the "leave it on" types. I leave most , if not all of my systems
on all the time, because, like scg, I don't like waiting for bootups. :)
I do turn some of them off durning thunderstorms, but will leave the ones that
are on a UPS turned on.  For example, there's been several storms since I last
rebooted my Linux box 103 days ago, and it's still going. I even lave my lptop
in suspend mode most of the time, sometimes for up to 2 days.I've also found
an interesting setting that's appearing in newer motherboards where it will
turn itself on after a power failure. Nice thing to have, especially for a
server machine. 
On the subject of monitors, in my case I've seen an odd thing. I have an old
CTX 17" that I got from property dispo, and aside from a minimal bit of
burn-in and a jitter problem at low refresh rates, it's a good monitor. I
leave it on all the time, except when it goes into sleep mode when the screen
is blank. My roomie purchased a 19" Komodo a few months back, and he turns
it off whenever he's not at the machine, but with it being on a computer that
everyone in the house uses, it usually gets turned on again rather soon. Then
off again, then on.... Now it's developed this problem where all of the red
in the image takes 5 or so minutes to "pop" in, and the problem is only
getting worse with every power cycle. I tried to tell him to either leave it
on, or take it in to get it fixed, but he won't listen. He also turns his
computers on and off all the time, an they're about the same in how unstable
they are. 
Guess you could take it two ways. Leave the computers on, or don't let my
roomie build a computer. :)

response 11 of 20:

Feb 20 01:43 UTC 2001

For me it depends what the machine's doing.  A lot of older
machines lacked power management, but can be coaxed into
spinning down the hard disk if it's not been used for (say)
twenty minutes.

Wherever possible I enable display power management
signalling (DPMS), to blank the screen and go into a 'light
sleep' after five minutes, and go into a 'deeper sleep' or
stand-by after some longer period, say another ten minutes.
Where DPMS isn't an option, I make the screen-saver blank
the screen, and ask people to turn off their monitors before
leaving for the night.

I would like to configure more of our PCs to go into standby
if left alone for half an hour, but because of existing
inter-dependencies they have to be powered up in a specific
sequence and it's proven easier to leave the system unit on
and have the disk an monitor power down in an effort to
conserve power. The machines run the SETI@home screen-saver,
so their spare processor time is put to some use.  Most of
them will be retiring from the SETI@home project though, and
will be switched off over-night.

Incidentally, anyone know how to configure a PC with 'soft-
power' to automatically turn on at a given time?

response 13 of 20:

Feb 20 18:22 UTC 2001

Thanks gull, I'll see if I can find that one.

response 15 of 20:

Dec 18 01:06 UTC 2001

I've replaced mine, but only because I wanted an amp with a Dolby 
Digital and Dolby Pro Logic decoder.  The Fisher also needs new filter 
capacitors, it's developed a nasty hum.  I'll probably replace the 
filter caps and then sell it.

response 17 of 20:

Jan 12 14:36 UTC 2005

The biggest failure items are the rectifier diodes.  These sets were
originally equipped with selenium rectifiers.  When they go, they
release noxious fumes and can start a fire.  My set had already had them
replaced with modern silicon rectifiers.

response 19 of 20:

Jan 23 22:56 UTC 2005

Heehee.

It certainly puts out a lot more volume than you'd expect, based on its
specifications.  It's rated in good, honest RMS watts, though, not the
"peak" watts that you see in ads these days.