Almost all ergonomics professionals agree that taking breaks during typing is essential for preventing and recovering from RSI. There are 3 types of breaks a typist should take.
Eye breaks: Looking at a computer screen causes your eyes to blink less often which exposes your eye surface to air for more time. This can cause changes in how your eyes normally function. Every 15 minutes or so you should look at a distant object or scene more than 20 feet away for a 30 seconds to 2 minutes, depending on your eye strain. Every 30 minutes you should also blink your eyes rapidly for 10 seconds. This refreshes the tear film and clears dust from the eye surface.
Micro-breaks: Occupational studies reveal that typing occurs mostly in short bursts of activity, not as a continuous activity. Between these typing bursts you should do something to break the repetitive nature of the typing activity. Performing a brief stretch, standing up or moving around can all do this. Section below lists various types of professionally designed micro-break exercises which you can perform to relieve the typing-induced tension. A micro-break is not a break from your usual activities but rather a break from the repetitive nature of your activities. Micro-breaks are vital for RSI prevention.
Rest-breaks: Every 60 - 90 minutes a brief rest break should be taken. These breaks usually span between 2 to 5 minutes or even longer depending on the strain. During these breaks it is recommended that you stand up and move around. Get a glass of water, soda or coffee for example. It is also important to do some small exercise to relieve muscle fatigue. Rest breaks give other muscles a chance to work, which helps relieve fatigue and increase stamina. If you already experience RSI pain, then timing these breaks is extremely important. See how long you can type without experiencing pain, tingling or numbness then subtract 10 minutes from that. This period should be the amount of time you type before taking a break.