My first chair was too big. The enormous leather monstrosity offered no back support and I had to stretch my arms flat to reach the armrests. It was too low for my desk and couldn't be adjusted properly so I sat on my feet or crossed my legs for height. Besides, it swiveled too easily, leaving me unstable.

My second chair was too small. Cute and covered in a cowprint material, it was adjustable but offered no lumbar support or armrests. If I leaned back, I was in danger of falling over.

But my third chair is just right. It's a $500 ergonomically designed, fully adjustable model -- the first two chairs cost less than $100 each. In my quest to find suitable seating, I learned that a great chair quickly pays for itself in increased productivity and decreased downtime. My bad chairs gave me headaches, muscle tension and wrist-strain. Now, I have a renewed love of work, improved quality of life and I save the costs of physiotherapy, Aspirin and sick days.

What to look for:
Feel
Many people test chairs by sitting in an awkward position, with their backs ramrod straight or slouched. Test it by sitting the way you want to sit after adjusting it to your size. If your back naturally presses against the back of the chair and you feel comfortable and supported, then it is probably the chair for you.

Flexibility
You should be able to customize your chair, adjusting it so that your feet are flat on the floor and your knees make an angle of about 100 degrees. Your armrests should move independently -- position them so your forearms are supported and your shoulders are relaxed.

Control
The chair's mobility should vary in degree and optionally lock, so that it will not roll away at the slightest push. You should be able to swivel to the side gradually and stay there without making a full rotation, and lean back slightly without danger of falling over backwards.

Material
Leather may look prestigious but it can be slippery or sticky in hot weather. This material also tends to lose its shape and rips easily. Opt for a chair that has an absorbent, breathable material cover with soft -- but firm -- padding, a steel spine, beveled plastic armrests and solid footing.

Top-of-the-line chairs may be expensive, generally ranging anywhere from $300 to $700. But a good chair will last longer, decrease your likelihood of acquiring stress- and strain-related ailments, and increase your productivity. It's a good investment.

Creating an ergonomically-sound work environment
• Your monitor should be directly in front of your face and you shouldn't have to incline your neck to get a good view.

• Your work room should be well ventilated and lit, ensuring that no light source (including sunlight) causes glare.

• Your keyboard should be level to - or slightly below - your armrests so your hands fall gently and your wrists are flat while typing. Clean or replace sticky keyboards.

• A plastic mat provides mobility and stability on a slippery or thickly carpeted floor.

• Make sure your mouse fits your hand – bigger is not always better.

• If you talk on the phone while working, try using a headset.