How can you ensure long-term memory?

[Gucamole]

I have a question for accomplished Network Engineers: How do you effectively retain the information you learn over the long term? Do you regularly practice lab exercises or revisit materials? Or does the knowledge tend to stick in your memory once acquired? Currently working as a Network Engineer with CCNP, and in trenches.
For instance, a few years back, I dedicated extensive hours to mastering concepts such as routing, switching, Route-maps, prefix-lists, etc with labs and creating detail notes (notebooks, Mind-maps etc).

I have also successfully implemented these in various projects, receiving commendations for my work. However, with changes being relatively infrequent, the details tend to fade from memory over time. When faced with the need to recall specifics, I often find myself uncertain, relying on vague recollections.
While I can refresh my understanding through reading and practical exercises, the demands of family life limit the time I can devote to this endeavor. Consequently, during impromptu design meetings, I sometimes struggle to recall details confidently. How can one contribute effectively in such situations without appearing unsure of their expertise?
In summary, what strategies do you employ to maintain proficiency in networking concepts over the long haul?

[bigevilbeard]

I’m not sure I’m “accomplished”.. but let’s see. You're right on point – retaining all the network engineering details over time can be a challenge, especially with a busy life, family, hobbies and the notion “use it of lose it”. Overtime stuff falls to the old grey matter at the back of your memory. Nowadays I tried not to remember everything I once knew/learnt, but I like to stay in a  comfortable space of knowledge. Couple of things help me, dedicate a small amount of time each week to staying updated on industry trends and new technologies. Reading relevant blogs, attending webinars, or listening to tech podcasts during the day. My personal favourite is the community. 
Participating in online forums or local meetups allows you to discuss challenges with other engineers, refresh your knowledge through shared experiences, and potentially even learn new approaches.

Finally. It's okay not to know everything! During meetings, it's perfectly fine to acknowledge you need to refresh your memory on a specific detail, rather than trying BS your way through.

[Richard Burts]

@bigevilbeard makes some good points. I would add that forums like this one are a very good way to stay up to date and to refresh details of things that you learned a while back.

[Joseph W. Doherty]

Personally, I find retaining fundamental concept pretty easy, long term, if you truly understand them.

The day-to-day stuff, I only tend to remember if I'm using it day-to-day, I can always look something up.

Fundamental concepts also (usually) tend to change/evolve slowly.  Day-to-day stuff, can change overnight, like with a new IOS release.

So, I would suggest, not worrying too much about remembering how exactly you do something, if you don't have a need to do that thing.  But, again, if you truly understood the underlying concepts, if the need arises again, for knowing specifics, often you'll find even skimming the documentation, much will fall again into place.

Even with current specifics, every jump (first time) into another vendor's network configuration setups, which are totally unlike classical IOS?  How easily you can process with vendor X equipment, often has more to do with truly understanding what you're trying to accomplish, other than we always use this set of commands to do whatever.