I feel like I have to disagree here. I don't practice e.g. multiplication or doing math in my head everyday or for years really, but I feel like I'm just as fast at it as I ever was. In fact whenever I have tried things like Lumosity or brain benching games, that I used to do when I was younger, I'm actually faster than when I was younger, despite not having practiced it at all. I feel like all the real world side practice has helped me improve these abilities indirectly, they have all added to my brain's ability to notice novel patterns, see things from different perspectives, apply new intuitive strategies, that I might have not noticed because I was tunnel visioning when I was younger.

There's also plenty of things that I have got for life just by having practiced them when I was child. E.g. I think everyone gets bicycling, but there's also handstand, walking on hands, etc, which I learned as a kid for few years, and I can still do it even if I only do it once a year. In my view code is exactly the same, and maybe in a way even more straightforward, it's easier than obscure math since you don't have to memorize any formulas to solve it easily, albeit I think a lot of math is great because you don't have to memorize formulas in the first place you just have to internalize or figure out the logic or the idea behind it, and then you just have it. I think repetition in math is specifically the wrong way to go about it, it's about understanding, not repetition.