i force myself to take regular breaks...i set timers! no sewing/working for more than 45 minutes at a time...when the timer goes off i have to stop...to shut the stupid/annoying thing off...then i actually take a break...get a drink, look through the mail, make a phone call,do some stretches, exercise; what ever...15 minutes...then reset the timer and go back to sewing...i have found i am much more productive and much less sore at the end of the day when i take regular breaks.