In my recent post "One Step at a Time" I offhandedly mentioned how ramping back up a skill you haven't kept honed involved wasted time getting back up to speed. Turns out that Alexander Hellene was on the same wavelength:
I picked up a guitar a few days ago for the first time in months and woo boy, was I struggling. I mean, it wasn’t like I completely forgot how to play, but the fluidity and the ease just weren’t there. Thank God for muscle memory, or else my fingers would’ve been nearly completely useless.
I used to be a musician. Not in the sense that one ever stops knowing about music or how to play it, but I mean a gigging musician. And I was good at what I did, mostly bass guitar, but I could pick up most instruments and just figure them out. The last time I seriously played anything was 2012, and I ended up selling the vast bulk of my gear in 2014, so it’s been a while since I’ve done anything more than strum my acoustic guitar . . . the same one I struggled with recently.
I put the guitar back in the case, not depressed but bemused. There’s a lesson here: keep your skills sharp.
Go read the whole thing, but it's funny, because I picked guitar after realizing that I'd spent so many years away from the violin I played for 5 years in school that just the time to get my basic finger positions remotely right so the notes weren't horribly off would be painful.
It's also interesting because while I likely could have simply crammed the night before to make my way through nuke power school in the late 80's and still passed, the reason I topped out my class was because I actually took notes every class, did the work a little each day, and actually did spend at least a little time beyond the homework studying/reviewing past material each day instead of ignoring it all. It certainly made it easier to draw connections to the foundational material.
I also see it in coding. I spent several years developing CMS's for websites and backend/front end as well. Could I relearn it? Sure. But I'd have to knock a lot of rust off before could start even getting up to speed on the changes since I was up to date. I run into it every time I decide to take a peek at learning or extending my programming skills again - it's a lot of work just to get the tools and development environments back into place and to get oriented.
Finally, I see it in language. Of the languages I learned before preschool, one I no longer speak or recognize. The other I used through my teen years with family, but at this time, while I can understand it, have difficulty constructing sentences and ideas in it without recent reminders or practice. If conversing with someone in it, my facility notably improves even over the course of a half hour. From a cold start? Forget it. I sound like a halting idiot.
In short - any skill you want to keep at hand, practice it regularly.
When push comes to shove, you perform how you practice.