As for deferred (repeating) tasks…
A Due date should only be used for items that really have a deadline.
A Defer or Star By date is for items where you say “I probably should get the Easter stuff out the week before Easter and not during Christmas”
Deferred focussed/starred tasks make it easy to have your own virtual secratary putting things in front of you at the right time.
Now when it comes to repeating, the difference between a repeating due task and a deferred one is that due is always due. Example: rent payment. Defer Again (or Start Again) has more to do with frequency. Example: watering the plants. If I want to water my plants every 4 days and I check off the task today, I want it to reappear in 4 days or on the 4th day.
In a task view like Focus the visible difference between the 2 is:
- repeating due will create multiple tasks for each time the task is due
- repeating deferred/start by creates one tasks which is removed once it has been completed and will reappear after the set delay
I have so many things on auto pilot this way in OmniFocus, it’s not a feature I would want to miss