Two words: spaced repetition
Combining both: better memory encoding techniques and spaced retrieval is the holy grail. People who employ both feel like superhuman. For example, you can encode knowledge of a book with a mind map following specific principles and then schedule either a spaced cued recall with image occlusion or a spaced free recall or a mixture of cued/free by occluding large portions of the mind map.
In my experience though, I rarely need spaced repetition for knowledge I’ve encoded with a mind map. I have almost perfect recall of the map and an understanding of what it represents many weeks later with no repetition.