rsl12 Beautiful, and how nice that you have Clair de Lune ready to go at any time! I'm a little jealous.
Hmmm.... sometimes, for jealousy there's a reasonable remedy 😉
I'm going to split this reply into two forks.
First, as to Clair de Lune specifically... after sporadic piano lessons in my early teens (didn't get out of John Thompson's Book 2 with one teacher and learned to play some songs building chords in a Ukelele Ike songbook with a second), I had a couple of months with a really good teacher in 1963 (my last piano lessons). One of the pieces he gave me was Clair de Lune.
So having worked on it and memorized it when my brain was young, it has stuck. It gets sloppy and I need to pull out the music and fix my faulty memory from time to time. But it's generally available to the extent that I can hack through it on the spur of the moment. @danno858 has heard me play through it sloppily when I hadn't played it in some months.
But that's an outlier piece for me. There are other pieces I can sit down and play that I've learned in my 70s.
I started a thread on this forum a few months ago addressing the topic of keeping at least a few pieces in one's hands that one can play reasonably confidently on the spur of the moment.
I used to like to go into piano stores and try out pianos, and wanted to have some things I could play from memory. (Sadly, in this area piano stores are now but a fond memory.) Or occasionally I'd run into a piano at a friend's house, or in a hotel lobby.
I practice piano because... (drumroll) I like to play. I don't practice just so I can do more practice. Or work on a piece and then forget it because I'm onto the next thing. Right now, I'm back to practicing the Barcarolle because I may have a chance to play it next month.
This is the thread where I started a discussion about keeping a few pieces playable in the fingers.
https://forum.pianotell.com/d/2069-more-thoughts-on-new-pieces-shiny-new-objects-versus-hoarding
So, @rsl12 , whether Clair de Lune or something else, I'd suggest you think about having at least a couple of things you like ready to go at any time. You may find that playing slowly through them every week or two is enough to keep them available.