Spaced repetition is good for pure memorisation but I'm not so convinced it is an effective or even helpful way of learning programming --- it seems it would just make you fixate on syntax and not truly understand things.
One way I like to think about it is as a continuum - there are certain things you use everyday and thus in a sense over learn. Then there are things you only use once or twice in your life, such as a specific configuration you have to do. Code Cards is for the things in the middle, the things you only use every now and then but keep forgetting and having to google over and over again.
In terms of using it as an aid for people learning programming, I think if you spend 4 hours a day effectively coding, then spending 5-10% of that time reinforcing some of the things you've learned during the day is not a bad use of your time.
A critical factor here, though, is that it's very clear from the spaced repetition/testing literature that the way you learn beforehand affects retention. (e.g. Karpicke and Roediger 2008).
Rather than trying to remember how to do a hundred trivial tasks correctly I focus on the task at hand and keep the reference document up on the other page.
I find it more valuable to have up to date and practiced referencing skills than to memorize a few hundred utility functions.
As an added bonus there's an intrinsic passive search for new techniques and depreciated methods.
Rule 1 and 2 from https://www.supermemo.com/en/articles/20rules are these:
> 1. Do not learn if you do not understand
> 2. Learn before you memorize
I use Anki to retain programming snippets and gotchas in the same way that Derek Sivers describes here:
This article cited there is well worth reading too, as it's specific to programming:
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_...
In the end, I determined that I learned a lot more from making the cards than I did from studying them.
So yeah, it was a win... But hardly the way I expected.
I found the same thing. The discipline of boiling things down into their essentials really forced me to pay attention and really thinking about the reading material.