[marcosdumay]

I imagine there's a lot of value in "I won't change from this task until the timer beeps, no matter what happens" and no value at all (or a lot of negative value) in "I will change from this task as soon as the timer beeps".

Pomodoro may be something worth adjusting. I do have to try it someday...

[gmfawcett]

One value of the latter is, "I will stop for a five-minute break before the next work interval -- just to stand up and stretch and breathe." It may seem like an unwanted interruption if you are "flowing," but it can enable much longer periods of sustained work.