Three and a half minutes is a brewing-and-listening sort of length — close to the time black tea wants to steep, roughly the length of a typical song, and a touch past a three-minute boxing round. It suits any task where three minutes runs out just a little too soon.
Three rounds of 3:30 is ten and a half minutes. Open the editor and set the rounds whenever you need the same stretch more than once.
A 2 minute 30 second timer — 2.5 minutes, for steeping tea, a recipe step, or a short meditation. Repeats as many times as you set.
A 4 minute 30 second timer — 4:30, roughly a song or a French press brew. Repeats as many times as you set.