Combine interleaving with spacing

Spread interleaved sessions across days so mixing and forgetting both do their work.

Why it works

Interleaving and spacing are partly the same coin: mixing topics naturally inserts gaps between repetitions of any one topic, forcing harder retrieval. Deliberately spacing the interleaved sessions across days compounds this, because each return requires reconstructing the memory rather than topping up a still-fresh one.

How to do it

1. Schedule several shorter mixed sessions across days instead of one long mixed session.
2. Let enough time pass between sessions that earlier items feel slightly forgotten.
3. Keep the mix consistent so each topic recurs at growing intervals.

Evidence

Spacing effects are among the most replicated findings in learning research, and interleaving inherently spaces each topic. Combining them is well grounded, though their independent contributions are hard to fully separate in a single study. (rct)

Because interleaving and spacing are confounded by design, part of interleaving’s benefit may simply be the spacing it introduces.

Common mistake

Cramming all the interleaved practice into one marathon session, which keeps the mix but throws away the spacing that does much of the heavy lifting.