In my little money making Internet endeavor (I never call it a business ) I get in the zone and can set for hours at the computer.
Setting for hours affected my health, I won't go into details, suffice it to say most of us know the problems that can be caused by setting for long periods of time.
I was determined to "take breaks," i.e. stand up and move around every 20 minutes or so, but as I said, when in the zone, time gets away from me.
My Solution. Divide my work station from one every thing within arm's reach to three different places in my home.
My pc in one room, printer in another, and smart phone, which I use as much as my pc in another place.
I now have to move around to get my work done. I feel much better and the spread out work station makes me more productive than ever.
How do you handle long work periods?