I did field work for about three years; repairing, updating and installing computers, so I sat at a lot of different system, and it’s my general opinion that, by far, most people have ergonomically-incorrect layouts.  Sometimes it simply can’t be helped, but usually — sometimes with a bit of creativity — most hurdles can be overcome.

This also grants quickly that people are different in every way imaginable; height, width, weight, posture, eyesight, and, for that matter, what you might call ‘intensity’.  You might find yourself sitting straight up, if not leaning forward, while writing something serious, then laid back while reading a long article, so there are a lot of variables going on.

So I’m not saying, by any means, that these are the ‘correct’ methods, just what I’ve gleaned over the years from reading about the subject, watching people have problems with certain system conditions, and my own body’s feedback.

I have been sitting at a computer console more or less 16 hours a day for 20 years, loving every minute of it, and have never, to this minute, had the slightest pang or ache.  Certainly not the tiniest twinge of Carpal Tunnel Syndrome, nor any back or leg pains.

The voice of experience is speaking.
 

The Chair

Let’s start with the basics.  I strongly recommend a chair with padded arms, and make sure the arms feel high enough that they’re comfortable.  There are a few models out there with low arms which are even worse than no arms at all, in that you end up crunching down one side of your body just to use the dang thing.

Good seat padding is an absolute must, of course.

So are rollers, but when it comes to what they’re rolling on, there’s a problem.  Footrests don’t work with those hard plastic pads that protect the carpet, because by the time your foot is firmly against the footrest, you’re pushing yourself backward.

The problem is, if you skitter back and forth on a regular carpet over a period of time you’ll start wearing it out.  One solution might be to put down a thin oriental rug on top of the original carpet, but then the problem is that there’s too much sinkage and the damn chair’s hard to move.  Another solution might be to move the monitor and keyboard occasionally, a foot or two to one side, or just move the whole system to keep from wearing out the rug.

As far as the footrest goes, I’d attribute always having a good footrest as a big part of why I’ve never had any leg or back pains.  The one thing it needs to be is solidly in place, because you need to push against it slightly.  I use a small suitcase filled with old books, with a pillow on top of it.
 

Size & Style of Tabletop

Back in the old days, when peripheral devices (printers, scanners, monitors, etc) were huge, I used a 4′ x 8′ piece of Varathaned plywood as my tabletop.  These days, with LCD monitors and ultra-thin everything else, a regular computer desk works just fine.

Besides tabletop space, the one key element is height.  You don’t want your monitor too high and you don’t want your keyboard too low.  I’ll address each specifically later.
 

The Tower

Noise is as much of an undue distraction as anything physical.  And it is physical, in the sense that it’s making your eardrums work overtime.

If your hard drive whines, junk it and buy a Western Digital, IBM or Seagate.  You should not be able to hear your hard drive at all.

If your CPU fan sounds like a B-52 taking off, buy a ‘flower’ heat sink with a variable speed control, like the Zalman.  You could also try putting a ‘motor control’ on your present CPU fan, but you’d want to run a CPU heat-sensing program and monitor things carefully.  The only way I can get away running mine at a whisper-quiet 1670 RPM is because of the special heat sink.

Update: My new Compaq has a variable-speed fan that increases as more CPU power is used.  I found it kind of annoying at first, but then discovered that it makes a great ‘program done’ indicator for programs that don’t have a ‘ding’ sound when finished.  When I hear the CPU fan drop back to ‘low’, I know the program is through.

If the fan in the back of your power supply is blowing a gale, go find an electronic parts dealer or get online and replace it with one that blows at half the rate.  The rate will be printed on the fan.  Alternately, if you have an old power supply, you can probably use its fan.  I had a 350-watt power supply that came with one of those B-52 fans.  I replaced it with the one from a dead 200-watt supply and it worked fine.
 

Keyboard

Keyboard height is critical.  If you’re feeling small shooting pains in your arms or back, most likely it’s either the chair, the height of the keyboard, or both.  This ‘new wave’ of pull-out keyboard drawers (built into the desk) are certainly convenient, but they’re usually too low.

Make an experiment:

Swivel your chair to the side, then hold your arms out like they’re on a keyboard.  Hold them there, raise and lower them, and find a position where it seems like you could hold them there for a while without getting tired.  Chances are, they’ll be slightly above level.

Now hold your arms in place and swing back to the computer desk, and that’s where your keyboard should be.  You should take whatever pains necessary to get your keyboard into the right position and height.  Otherwise, you really will be ‘taking pains’.
 

Wrist Support

Unfortunately, the only way to really do this right takes some effort.  The trouble with wrist supports is that the only place they can sit is on the same tabletop as the keyboard, so they raise your hands too high and your fingers end up kind of dropping down on top of the keys, whereas they really should feel like they’re ‘rising up’ to the keys, following the gentle rise provided by the legs in the back of the keyboard.  If your keyboard’s legs aren’t down, use them.

If you’re handy with a drill gun and wood, the proper wrist support is a small shelf that extends beyond the edge of the desktop, and is lower so that, by the time you put a padded wrist support on it, it’s back up to level with the desk.
 

Mouse

The bottom line is that you really need to rig up some kind of elbow support if you use your mouse a lot.  A wrist support just isn’t enough over the long term.  You need something that’ll comfortably support your forearm, like a pillow on top of a card table, a small file cabinet, one of those old-type ‘telephone tables’ for hallways, whatever you can rig up.
 

Monitor

There are six things to cover:

Height — The middle of the monitor should be about eye level or slightly lower.  The last thing you want to do is crane your neck upward or downward for hours on end.  If it’s an old-style CRT (not an LCD) and it’s too tall, try removing the stand.  If it then leans too far back, prop up the back side with a book to level it.

Size — This is dependent upon two things; how far it is away from you, and the resolution.

Resolution — You want 10-point (non-bold) text to be nice and readable, all of which depends upon how far away the monitor is and its size.  Most news and blogsites are 10-point non-bold.  Unfortunately, the computer manufacturers in recent years have decided that the public wants ultra-tiny text and is making 1280 x 1024 the default screen resolution.  For a standard 17" to 19" monitor (or 20" LCD), this is WAY too big.

Click on the Desktop with the right mouse button, open ‘Properties’.  Click on the ‘Settings’ tab.  If it’s not, move the slider to the "1024 x 768" position.  Things will look gigantic for a while, but this is really the proper resolution for that size monitor, and is the size most web pages are designed for.

Distance from eyes — This should be your fine-tuning tool.  Get the size you want, the resolution you want, then inch the monitor forward or back so that everything looks perfect.  If you have to move it too far either way and it doesn’t feel right, change one of the other parameters.

One other thing that affects text readability, especially web pages, is whether or not your ‘ClearType’ fonts are turned on.  Click on the Desktop with the RMB, open ‘Properties’, ‘Appearance’ tab, ‘Effects’. If the ‘ClearType’ fonts are on, turn them off and see how some web text looks.  If you want to experiment, open a web page, then squeeze the browser down to half the screen size, then turn the ClearType fonts on and off, hitting the ‘Apply’ button.  ’ClearType’ fonts were designed for LCD monitors but I think mine looks better with them off.

There’s a very easy test to see if your monitor is too large and/or too close.  This’ll be hard to do yourself, since you’ll be conscious of it, so tell someone to sneak up unaware sometime while you’re reading something that spans the width of the screen, like an unmargined Web page, and see if your head is moving side to side.

If it is, that’s the big no-no.  Only your eyes should be moving.  You count up each tiny little muscle twitch in your neck as you move your head endlessly side to side, side to side, and that’s 10,000 muscle twitches a day.  Seriously ergonomically bad.

So those are the two test questions:

1.  Does your head move side to side when reading text spanning the full width of the screen?

2.  Do you find yourself leaning forward to read normal text?

A ‘yes’ answer to either one means that something is ergonomically wrong, and your neck, back and/or shoulders will pay for it.  I would note that it’s certainly natural to lean slightly forward to see some tiny detail or read some minuscule text, but there’s a difference between that, and actually craning your neck forward.  Ergonomically, it’s probably better to feel like the monitor’s too close, and feel like pushing back from it slightly, then having it be too far away and constantly on the verge of leaning slightly forward.
 

Lighting

Ambient lighting is certainly the nicest way to go, but, in lieu of that, I’d suggest a bunch of small table lamps, 25-watt bulbs on a dimmer, placed generally about the room but without reflecting in the monitor.  "Zero Glare" is Rule #1 in the graphic world.