A free 10-minute timer, one tap to start. Ten minutes is just long enough to get one real thing done: a single task finished properly, a quick review, or a short focused read. It sits at the bottom edge of what counts as a focus block, so it is ideal for one contained job and less suited to deep work or brand-new material.
Where five minutes is for starting, ten is enough to actually finish one small, contained job, an email thread, a form, a quick fix, done properly rather than rushed.
A fast pass back over something you already know: a short set of flashcards, your notes from last session, the key points before a meeting. For a full review session, the 15-minute timer gives you more room.
Ten undistracted minutes is enough to get properly into an article or a section of a chapter, as long as you are not trying to absorb something brand new and dense.
Long enough to plan your day, outline a piece of work, or think a small problem through on paper, away from the doing.
Ten minutes sits right at the bottom edge of what the research treats as a real focus block. In his most generous estimate, Tony Buzan put the ideal study interval at 10 to 45 minutes[1]; in most of his editions the range starts higher, at around 20 minutes[2], because anything shorter does not give your mind time to settle into the material. So ten minutes is about as short as a focus block can be while still counting as one, and only just.
That makes it a good length for one contained thing, finishing a small task, a quick review, a short read, rather than for deep work or learning something genuinely new. For those, give yourself longer: the 15-minute timer for a proper review, 20 or 25 minutes once you are studying or working in earnest. Ten minutes is the floor, so use it when ten minutes is what you have, and step up when you can. It is about what the task needs and what works for you.
Ten minutes is enough for one job done properly, not three half-started. Pick the single most useful thing, close everything else, and see it through. If it turns out to need longer, that is not a failure, it is a sign the task wants a 20- or 25-minute block.