It's not that one day you can do it & the next day you can't. It's more like one day you don't do it & the next day you can't.
I'm quoting myself to explain why I have to keep going to karate ~ the day I stop will be, I fear, the beginning of the end of my physically & mentally active life. Although today I was mostly trying to paste over my usual deer-in-headlights look that I get whenever we do weapons.
My grandma, a piano teacher, used to say that every day you don't practice you slip back two. Same idea.