Do you sit at a computer screen all day? Does this cause repetitive stress syndrome, eye strain, or mobility problems? You can combat these problems by using several free or inexpensive software applications that urge you to take breaks. You can configure them to do many things, including darkening your screen and halting your work until you tell it to postpone or skip the break.
I work on both PC and Mac, and my favorites for each platform are both free: Big Stretch Reminder for PC, and Dejal Time Out for Mac. Both of them can gently remind you to take a break on a regular basis, and are quite customizable.
Big Stretch Reminder (PC):
With Big Stretch Reminder, you can configure the time between breaks, the length of the breaks, or the time of the break. You can create your own custom reminder and choose how to be reminded, from a gentle reminder to an intrusive work stoppage. It will allow you to postpone or skip the break. There are reminders in the form of dialog boxes and audio alerts, all customizable. See http://www.monkeymatt.com/bigstretch/.
Dejal Time Out (Mac)
Time Out lets you configure two kinds of breaks: a longer break to move, stretch and relax, plus a “Micro” break which is a very brief pause of a few seconds every few minutes. You can set how long each kind of break lasts and how long between. Time outs are announced by slowly dimming the screen. You can even run an Automator workflow, AppleScript, Python script, or application at the start and/or end of each break. This would allow you to listen to music or play a video, for example, during the break. When the break is finished, the screen resumes. You can pause or skip each break. See http://www.dejal.com/timeout/.