Just for kicks I decided to listen to my recording of Sidiyasa, which was really the first rhythm I worked on for any length of time. (And boy, we worked on it for months!)
It was humbling. After playing these parts every week, over and over again until I could hear them in my sleep, today I was totally confused by what I was hearing on the recording. I had to go find my notebook to sort out the handing of the rhythms. That floored me. In some cases it was like I was hearing them for the first time.
It was a powerful lesson that I will have to keep practicing the old rhythms even while I am learning new ones, or I will just lose them. It also reinforced the value of writing them down, even though now I don't have to do that to be able to work on them. But months from now, when Sounou is a distant memory, I will likely forget how it works if I don't keep a record of it somewhere.
I have found that with the piano pieces I knew, too. At one point I could play them blindfolded, from memory. Now I can only remember little bits and pieces, and even looking at the music, it is like trying to read Greek.
So, today, I am going to write crib notes for Wassolonka and Sounou and Dansa so that in the future, I won't lose them.