A 5 minute timer is the smallest block worth setting. It is short enough that starting costs almost nothing, which makes it the right tool for the task you keep avoiding: open the document, answer the one email, put the dishes away. Once the clock is running, the hardest part is usually behind you.
Five minutes also works as a hard stop. Use it to cap a break, a stretch, or a round of scrolling, so a pause stays a pause instead of turning into half an hour.
