Anything that happens on a schedule — lunch duty, a standing specials block, a weekly spelling test — should be written once and repeated, not retyped.
In the lesson editor, find This entry should appear and change it from once.
How often
once — a single entry on this date only. The default.

daily — the entry appears in this period every day.

The third option is named after your schedule. In a normal weekly planbook it reads weekly, meaning "this weekday, this period, every week". If your planbook uses a rotation it's labeled to match the cycle instead — "every other day" for A/B days, "every other week" for A/B weeks, "every 10 days" and so on.
This is what makes recurring plans survive a disrupted calendar: they follow the cycle, so a snow day pushes them along rather than knocking them out of step.
How long
Choosing daily or the cycle option reveals a second dropdown.
For daily entries:
- this week — this week only
- this week and forward — from this week to the end of the planbook
- for all weeks — the entire planbook, including weeks already past
For cycle entries:
- going forward — from this point to the end of the planbook
- for all weeks — the entire planbook
Use going forward when something starts partway through the year, and for all weeks for fixtures that were always there.
Editing a repeating plan
Opening a repeating entry and saving it updates the series. If you only meant to change one day, be aware that quick edit has no repeat control — editing a repeating entry there converts it to a one-time entry for that day, which is occasionally exactly what you want and occasionally a surprise.
A repeating plan doesn't have to be a lesson. Rotation labels are made this way — see Rotation labels.