I sometimes review old material. I don’t have any fixed plan for this, though. There is a podcast series I have worked through a while ago that I am currently repeating irregularely. I’ve merged all the lessons into a pdf and review them on my tablet, writing translations below those words I haven’t memorized.
I review old stuff if I like to have something easier that I can do for a longer time or that I can actually comprehend, as I usually have around 20-30% unknown word count in new lessons. It’s a good way for boosting ones motivation. If you have the feeling you make almost no progress, review something from 2-3 months ago. You’ll probably be surprised. 
I never review stuff that I have just finished, though. That’s never been my learning style in any subject. But that’s a personal preference.