How do you retain knowledge for things you learn about Rust (or anything really, frameworks, other languages etc.) when you aren't using it often?
Just a curious open question, not looking for like "the" answer
I feel like maybe some people do it by answering forum questions, others might be doing coding challenges outside their daily routine, and maybe some people have a fantastic memory and aren't as plagued by "use it or lose it"?
Instead of trying to actively remember things, I have gotten myself comfortable working with reference material and relearning things I used to know when I need them again. Having learned something before, the second time goes much faster.
Bookmark the really useful/insightful stuff for occasional reference or review
And keep your own notes / program snippets too
Follow good bloggers/vloggers, read release notes, track the upcoming features you care about
The more you love the language/framework/etc the easier this is
But I think there are also usually some "stars", I could write up my Rust favorites if useful
Help a friend learn it (or, yeah, forums)
Personally, having to explain something helps cement it in my mind, to the extent that when I'm thinking about something I'm learning, in my head I'm often explaining it to some imaginary person
Other people asking questions will make you learn things you haven't considered yourself or remember things you haven't thought of recently
Even being a passive participant and reading these things is beneficial, I feel
But all said there are a bazillion technologies and limited time, so you'll eventually be "neglecting" something. Fortunately I find much of the knowledge has a "riding a bike" quality, where the ahhhh, refresh period (let's not call it de-rusting ) is much shorter than the initial learning period. (But of course, everyone is different.)
iteration with increasing time between iterations will bring knowledge from short term into long term storage.
Learn something, wait an hour and learn it again. do that a few times then increase the interval. Learn it again the next day, then wait a day before you learn it again. Then wait two days and learn it again. Stretch the time till for more days, weeks till you almost forget, then learn it again. After a while the learned knowledge will stick in your brain in a place where you will take years to forget it.
I most often learn new concepts when writing code to solve a particular problem. In that process, I search for solutions and experiment until I find one I like. I use comments in the source code to explain why I picked that approach and anything that seems weird. I'll often include links to where I found the solution.
I then move on to the next problem, mostly forgetting the details of how I solved the last one. When I encounter a similar problem a week, month, or year later, I go back to the code I wrote before, using Github as my long term memory. Most often everything I learned back then comes flooding back. Even if it doesn't, I've got a template that gets me started.