[derangedHorse]

I think notes are generally a good idea to help you summarize the knowledge you've acquired while spaced repetition is the aspect that will help in retaining the knowledge you've learned. The important thing is that the notes are written in a way you understand and can be picked up and read-again with a limited amount of context. What I mean by 'limited context' is sometimes I forget big portions of what I've learned and writing notes as if I'm teaching someone who knows very little about the subject allows my future self to pick forgotten things up faster. I personally use one of the Anki apps to do this myself.

The best form of spaced repetition IMO is the application of the acquired knowledge in a big project over time. That way re-visiting the concepts comes naturally as you continue to develop something over time.