Also, switch to a trackball instead of a mouse. I'm not terribly sensitive to RSI (I've worked data entry jobs where I sometimes spent 12 hours a day 6 days a week typing), even so I've found that using a regular mouse for a full day of work is one of the easiest ways to get RSI. I switched to using a trackball maybe 10 years ago and it's very noticeable how much it improves things.