Having been through several bouts of RSI-type injuries, here's my advice:<p>1) take up active hobbies that strengthen vulnerable body parts. Rock climbing did wonders for keeping my De Quervain's tendinitis from returning.<p>2) stretching is an enormous part of recovery, if you've already developed tendinitis.<p>3) fix your posture. I didn't realize that I was craning my head forward over the years to compensate for poorly corrected astigmatism.<p>4) vary your environment. A convertible sit/stand desk along with an adjustable monitor arm should allow you to change up your position many times per day.<p>5) never spend extended periods with your arm extended to the mouse, resting your arm's weight on your wrist. This is probably the single worst thing for your wrists (aside from impact injury).<p>6) invest in a decent mechanical keyboard. Consistent, light key resistance is more important than ergonomic layouts, not that I have anything against properly executed ergo.<p>7) WALK! Get up, stretch your head back and your arms up. Go for a walk around the block while maintaining proper posture. No staring at your phone. It does wonders to reset your body and would have saved me years of pain if I'd done it regularly.