Truly, it really depends on what you mean by 'redoing theory'. Rewriting notes? If you're just redoing it you're not exposing yourself to new information or creating correlations inside your brain that kinda links everything together.
Personally I don't really "redo" theory.
I might find a youtube video on the topic to clarify and reemphasise information and just continue with different practice questions to expose myself to new possibilites.
If for an english-y subject, I'll write an essay with differing questions.
I'm an audio learner though, so youtube videos are great, it truly comes down to the individual. However, something else I do is write out the content on palm cards and occasionally skim through it and this really drills in info. Diagrams like flowcharts are especially helpful on these cards.
I don't rewrite content as there can be a lot and often it's time consuming.
In my opinion, re-reading + extra info for connections > redoing. Again, it's up to the individual and the subject.