Keeping Personal Cheat Sheets as a Software Engineer

I have been compiling a few [personal cheat sheets] through out the years as a
software engineer and have found they have become invaluable. The cheat sheets
were started to help me learn by typing the commands that I needed to remember.
For example, as I was learning vim, the commands to move up, down, left, and
right were put into the vim cheat sheet where I could quickly find it.

Personal Cheat Sheets take work to maintain and will require that they are
constantly updated. The knowledge you gain will change and you will find some
amazing gems of knowledge that you will want to keep. Review your sheets often
as some of the commands you will [forget over time] and it’s nice to get a
little refresher from time to time. You will also want a way to keep your cheat
sheets close by so you can easily get to them when needed.

How do you manage your knowledge? Old school notebooks? Note Cards? Git
repository? Or do you manage them in some other way?

[forget over time]: http://en.wikipedia.org/wiki/Forgetting_curve
[personal cheat sheets]: https://gist.github.com/JoshuaEstes/2627607