Also, every time you get the review right, your waiting time between reviews for that item becomes longer. It scales like this:
Apprentice 1 → Apprentice 2: 4 hours
Apprentice 2 → Apprentice 3: 4 hours
Apprentice 3 → Apprentice 4: 1 day - 1 hour
Apprentice 4 → Guru 1: 2 days - 1 hour
Guru 1 → Guru 2: 1 week - 1 hour
Guru 2 → Master: 2 weeks - 1 hour
Master → Enlightened: 1 month (30 days) - 1 hour
Enlightened → Burned: 4 months (120 days) - 1 hour
Also, for the first two levels, your Apprentice SRS periods are halved.
To get a grip on how many reviews you’ll get and when, have a look at the Ultimate Timeline: