Spaced-repetition learning is a core part of how I learn (and, most importantly, remember) almost anything, and has been for about five years now. But spaced repetition can be hard to get into because much of the discussion is domain-specific (either language-learning or medical-school study). Most people want to learn things outside those domains. So, here are some key readings that address other topics:
- How to Remember Anything Forever-ish, Nicky Case 2018
- How to write good prompts: using spaced repetition to create understanding, Andy Matuschak 2020
- Augmenting Long-term Memory, Michael Nielsen 2018
- (this talks about how he uses it to understand CS papers)
- Effective learning: Twenty rules of formulating knowledge (that’s by Piotr Wozniak, who invented SRS apps in the modern sense)
In my experience, spaced repetition is most useful for relatively-stable facts (rather than ideas, speculations, views etc) which I need to know sometimes, but not often enough to cause me to learn them naturally. E.g. one of the first things I used it for was to (re-) learn basic statistics, which I need once or twice a week. (that’s also the kind of thing you can’t just look up if you’re too ignorant or too rusty — you need some active knowledge in order to even know what to look up).
Cooking, gardening, using software X that you take up in anger only a few times a year — these are easy, high-yield uses too.
It can be used for less-factual matters, however. Using spaced repetition to make the most out of blog posts and books has some good examples of doing this.
The main trick to success, regardless of what you’re learning, is in how you write the cards. This is a craft skill that can take a long time to master — it took me at least a year to get good, and now I still often have to rewrite cards once or even twice before they work for me.
(related point — be aggressive at culling things that no longer matter to you. Don’t let your daily practice be wasted on things you don’t care about.)
WRT software, I use Anki exclusively. It’s the only thing I’ve tried, and as far as I can tell it’s the only game in town for my needs (mature, cloud sync, mobile and desktop apps).
Further, more specialised advice:
Advice for Anki specifically:
When Not Required 