While computers let you accomplish a whole lot, there are perils to spending too much time sitting in front of a computer, especially when you are mousing on a desk that is too high or too low because it forces your hand to reach up or reach down putting pressure on your wrist.
Putting pressure on your wrist is a problem because compression and extension of the wrist and corner of your hand causes the nerves that run through your wrist to be pressed on, causing numbness and pain in your fingers.
Developing some type of repetitive strain injury (RSI) like carpal tunnel syndrome (CTS) is the last thing you need specially if you work at a PC all day. Ideally, what you want is a natural resting position for your hand, which should be with a straight wrist and the palm of the hand resting at an angle (between 30 and 45 degrees) with the fingers curled.
Sitting higher on a desk and using a wrist pad gel with an ergonomic mouse like the Cherry MW 4500 are some solutions that can help you prevent putting too much pressure on your wrist.

Using a gaming chair, desk riser or sit-stand desk also helps as it allows you to stand up as well as easily adjust your sitting position without having to upgrade your desk or chair.
An ergonomic mouse is the cheapest and easiest solution one can implement on a desktop setup. Ergonomic mice come in all shapes, sizes and angles. You can get symmetrical mice like the Gentix symmetrical mouse, 90-degree vertical mice and near vertical angle mice like the Cherry MW 4500.
Having never tried an angled mouse before, the Cherry MW 4500 45 degree inclination feels comfortable in the hand as the palm and thumb sit on the mouse making the wrist straight, which effectively alleviates resting pressure.
The Cherry MW 4500 45-degree mouse comes with a DPI button, located just below the scrolling wheel, that lets you adjust the DPI sensitivity on the fly from 600 DPI, 900 DPI and 1200 DPI.
It's neat that the MW 4500 integrates a small led on the side of the mouse to let you know which DPI you have set (one flash = 600DPI, two flashes = 900 DPI, three flashes = 1200 DPI). When the led flashes rapidly that means the batteries are running low.
On the bottom of the Cherry MW 4500 angled mouse, you find an on/off switch, the AAA battery compartment and the nano receiver which stores neatly inside it.
Talking about batteries, the MW 4500 mouse integrates an energy saving mode that automatically puts the MW 4500 on sleep after 10 seconds of inactivity.