Twenty-four minutes is roughly a half-hour sitcom with the ads cut out, and just under the classic twenty-five-minute focus sprint — a single block long enough for real progress on a task, with no break to negotiate. It suits a deep-work stint, an episode-length wait, or a tidy time-box on a chore.
Run it twice with a break of your own and you have a near-hour session. In the editor, choose how many rounds to repeat the block, or use a timer that builds in the break when you want the rhythm handled for you.
An 18 minute timer — the length of a TED talk, and a tidy focus sprint. Repeats as many times as you set.
A 30 minute timer for cooking, a nap, a TV episode, study, or a parking meter. Repeats as many times as you set.