I think it strongly depends on how spaced repetition is being done. Spaced repetition of content isn't useful (simply viewing), but spaced testing is [1]. Also,

I think it strongly depends on how spaced repetition is being done. Spaced repetition of content isn't useful (simply viewing), but spaced testing is [1]. Also, a test might be just testing syntax (could only know answer via docs), or more syntax+conceptual (e.g. would know answer if you understood the concept of a pipe in x language). A big benefit of testing concepts is that people often overestimate how well they've learned something, so someone may think they have the concept down and that testing is unnecessary, which makes seeing spaced tests is a sort of long-term memory reality check. [1]: http://learninglab.psych.purdue.edu/downloads/2008_Karpicke_Roediger_Science.pdf http://learninglab.psych.purdue.edu/downloads/2008_Karpicke_...