Study at Home / Time

Short and frequent beats long and occasional

The re-entry cost is fixed, so frequency wins.

Getting back into a piece of work costs a fixed amount regardless of how long you then spend: remembering where you were, reopening things, recovering the thread. On a two-hour session that overhead is small. On four short sessions it is paid four times, which is the usual argument for long blocks.

The argument fails on availability. Long blocks require conditions most people cannot reliably arrange, so a plan built on them is a plan that frequently produces nothing at all, and nothing is worse than a session with overhead.

The practical resolution is to reduce the re-entry cost rather than the frequency. Stopping mid-task, leaving a note of the next action, and keeping the materials open all shrink it considerably, and once it is small the arithmetic favours frequency.

Frequency also maintains the thread. Studying four times a week for forty minutes keeps the material live in a way one long weekly session does not, and the accumulated recall difference is substantial over a term.

There is a further refinement to the re-entry problem worth adopting, which is to leave the note in the material itself rather than in a separate list. A line typed into the document where you stopped, saying what you were about to do, is found automatically when you reopen it, whereas a separate plan requires remembering that it exists.