Those who teach

Yeah there is research on this, too - it's usually called "learning by teaching," although there are other names, too, like the "protege effect": http://ideas.time.com/2011/11/30/the-protege-effect/

But generally, the idea is to help students learn, instead of just yourself. So, instead of lecturing, give them opportunities to explain the material to others, do study groups, etc. Even explaining material to yourself helps you understand it better (this is called the self-explanation effect, by Michelene Chi and others). So, you can embed prompts after questions that ask students to reflect and explain what they learned, or have students blog or keep a journal about their work (or contribute to stackoverflow, yahoo answers, or similar support forums).

Anyway, read How People Learn, a free book: http://www.nap.edu/catalog.php?record_id=9853

There's another important reason to teach.

A lot of people fall into the trap of building solutions for non-existent problems. (I certainly have) By going out of your way to help & teach others, you notice what problems people keep having, and what solutions currently exist.

Crassly put, teaching is the nice way to do market research.

Agreed. I'm coming up to a decade of teaching CS in high school as well. The best times are when I don't know the answer to something I've been asked (and considering my classes go down the rabbit hole with topics pretty frequently this happens a fair bit :) since not only do I have to go learn about it I also have to learn how best to explain it and ascertain understanding of it in my students. The best moments are finding a really great way of relaying a difficult concept and having my kids have that "ahah" moment.[1]

I also started studying Karate about 5 years ago, and being given lower grade classes to teach helped my understanding of my own technique immensely (sadly it did nothing to alleviate the fact I was a creaky old man of 31 when I started ;P).

[1] One of the problems of teaching a set level of students though is you tend to stagnate at that level without your own side projects, which get less attention because of the time factor. That's about the only regret I have with teaching as a profession.

There was an article in Science last year[1] that backs this anecdote up with statistics. Graduate students who teach in addition to performing research are better at designing experiments than students who perform research alone, despite the vast amount of time that teaching consumes.

[1] http://www.sciencemag.org/content/333/6045/1037.full

I've been focusing on the d3.js tag a lot lately. There's a lot of noise ("I want this graph. Can it be done?" type open ended questions), but it has been teaching me a lot and solidifying many things I kind of knew before into things I know. I hope I can get some form of career advancement out of it, but the effort is paying for itself so to speak.