Hold to confirm

A confirmation dialog asks a question the reader has already answered. They pressed Delete, so of course they mean it, and after the fourth dialog nobody is reading the sentence in the middle any more: the muscle memory is press, press, gone. Holding replaces that second press with a second of continued intent. The action cannot be committed by a reflex, because a reflex is a tap, and it cannot be committed by a misplaced click, because a misplaced click lifts. Nothing is asked and nothing has to be read. The guard is the duration.

The progress has to be visible for any of that to work, which is the craft in this pattern. A button that does nothing for the first four hundred milliseconds is a broken button, so the press has to be answered immediately: a ring filling, a bar sweeping the label, a fill rising through the control. That mark is also the cancel affordance, since it says what the reader has to do to escape (let go) and how long they have left to do it. Releasing early must land somewhere honest as well, which usually means saying plainly that nothing happened rather than silently resetting.

Duration is the whole calibration and it is unforgiving in both directions. Under about half a second the hold is indistinguishable from a slow click and stops guarding anything. Past about a second and a half it reads as the interface being broken or the network being slow, and readers let go to try again. Somewhere between six hundred milliseconds and one second is the usual answer, with the fill running slightly ahead of real time at the start so the control feels responsive. Anything genuinely irreversible still wants a typed confirmation instead, since the point there is to make the reader name the thing being destroyed.

The cost is discoverability, and it is real: a press and hold advertises nothing to someone who does not already press and hold. Nothing about a button says its press has to outlast a threshold, so the label has to say it (Hold to delete, not Delete), and the keyboard needs a path of its own, because holding Enter fires key repeat rather than one long press. Treat it as a guard on an action the reader has already chosen, never as the only way to reach one.