Since the mouse is in use almost constantly, the ergonomic mouse is one of the most important pieces of equipment a computer user can acquire. Vertical mice are a popular solution for many people because they require little learning curve and they alleviate many of the common symptoms of hand/mouse-related strain.
These mice are designed to reduce the strain on your hands and wrist tendons by eliminating the "claw" or "clamp" grip and putting you in a more natural "handshake" grip. If you spend more than a few hours per day on a computer, a vertical mouse is a wise investment in your health.
Discomfort while mousing can lead to serious problems over time. Vertical mice are ergonomically designed to transfer muscle use from the hand and wrist tendons to the larger muscles of the upper arm.