What happens if I don't complete a review
If you start a review but don’t get through all the cards scheduled, a couple of different things happen depending on the type of schedule you are using.
Smart schedules
This is pretty straightforward. Because smart schedules work for individual cards, any cards that you do complete are then scheduled for their next review as normal depending on your confidence scoring. Any cards that you didn’t manage to complete will be added to your next suggested review.
Custom schedules (fixed and increasing intervals)
Because both custom schedules work for a whole collection, if you don’t manage to review all the cards in a collection when scheduled to do so, Luna treats that review as incomplete. It doesn’t matter if you only managed to review 1 out of 20 cards, or if you reviewed 19 out of 20 cards, Luna acts the same and leaves the review date as due for that collection.
However, for each card that is reviewed, the card confidence is updated, so that will always show you an accurate rating whether or not you managed to complete the whole review.