[tonetegeatinst]

I mean I think the bigger issue is that, at least for me, unless I am regularly using a skill I learn I forget most if not all of it.

I trig, and calc 1 yet I hardly remember how to solve most problems because its not something I use regularly.

Same with subnetting or remembering certain programming languages.

I literally don't use these things 99% of the time and so I forget them. Sure I understand some of the basics and I could probably pick it back up way faster than someone who knows nothing but I am human.

[yoyohello13]

I was recently studying some basics of quantum computing and had to re-learn a bunch of linear algebra. I thought I had forgotten everything, but when I sat down to review the material I picked it up very quickly (much faster than when I was in undergrad). It was like riding a bike. I think we think we forget, but the knowledge is actually dormant and much easier to get back.

So I don't think forgotten knowledge is wasted, it's still valuable.