How spaced repetition works here
The point of spaced repetition is to ask a word just before you would have forgotten it. Parolina uses a fixed ladder of intervals, which is simple enough to predict and to argue with.
The ladder
Answer a word correctly and it comes back after 1 day. Then 2, 4, 7, 14, 30, 60 and 90 days — eight steps, one per correct answer in a row.
Get it wrong and it drops back to hours rather than days, and how far depends on the difficulty you marked: an easy word you missed returns in about a day, a hard one in about six hours. Marking difficulty honestly is what makes the queue useful.
Mastered, and after
Eight correct answers in a row and a word is mastered — it leaves the daily queue. It can resurface on a schedule you choose in Settings, monthly or quarterly, or never again if you would rather it did not.
The daily queue
The queue shows what is due today and nothing else, which is what keeps a session to a few minutes instead of a pile. The toolbar badge carries the same number, so you can see it without opening anything.
Reviews you do in the web app count towards the same schedule. A word answered on your phone is not due again on your laptop.