Our new digital flashcards use a spaced-repetition model, which means that the algorithm determines when you are on the verge of forgetting before you are shown the card again.
The system also considers your proficiency ratings. For example, if you've rated a card a 5, you won't see it again until you are proficient with the rest of deck.
There is currently no way to reset the entire deck's proficiency and go back to the beginning, but we're working on it!
If you have any questions, please contact us anytime! We're always happy to help. 😄