[coconino]

A couple of ways Repeat can work:

Setting the repeat function on a project causes the entire project to repeat based on the start or completion date, and there is no need to set repeats on any of the actions contained within the project. Checking off the actions within the project is not enough to invoke a repeat; the project itself must be marked manually as completed (green tick) before the repeat will occur. In OmniFocus, simply completing all the actions in a project isn't doesn't automatically complete the project.

On the other hand, a project can contain repeating actions without the project itself being a repeating project. In this case the repeat setting will create a new duplicate action within the project each time the repeat is invoked. This means that over time the project will contain increasing numbers of almost identical completed actions, with the only difference being the completed date.

It is worth experimenting with these different methods to see which is preferred, and it may be that each is suited to different types of projects or actions. For instance, a rolling shopping list might be handled as a single non-repeating project containing repeating actions, but a project for writing and sending Christmas cards (like I made today) would be best done as a repeating project.