Short answer: RSI.
Long answer: RSI forces you to prioritise your time as once you did not, because time is precious and you've so little to throw around on typing. The typing you do mush count.
I said it here, I put myself up to be snapshotted to preach at a new audience, I'll say it again and again and again.
Take care of your hands.
Justine talks of losing contact with people because she just can not return emails and sit on IM. I may have had a month away from the computer and landed a lovely job that is kind to my hands, but I'm still wary of typing. I'm tardy in replying to any email of significance and I'm not writing the millions of blog posts I'm thinking of because I still must choose every night after work. Facebook and twitter have become my communication channels of choice - they force me to keep it short. It's a means of staying in touch without my jolly bouncy sense of obligation stepping in and having me waffle on with my inane prattle and my typing capabilities for the day whittle down.
It's my choice, so I chose the prize and price. But.
One last thing: I know a fair number of you are in your teens and twenties and spending a vast amount of time at computers. If you’re not already taking care of your body now’s the time to get into good habits. Take frequent breaks, have an ergonomic set up, mouse with both hands, take up yoga/pilates/tai chi/some kind of something that’s all about putting you in touch with the muscles in your body, drink gallons of water, stay as fit as you can, go outdoors etc etc.
You only get one body. Trust me, it will turn on you if you don’t treat it right.
It will happen to you.