I don't think experience is replaceable. There are certain things in software that doesn't change. - solving the problem at hand. - solving it in the quickest

I don't think experience is replaceable. There are certain things in software that doesn't change. - solving the problem at hand. - solving it in the quickest time possible - the solution to the problem should not introduce new problems I think for experienced programmer such as yourself the knowledge that you "lose" or "decays" don't actually become useless. I think they will serve you in making better future decisions like for example what you are saying now. Realizing whether things are 'fads' or 'foundational ideas' is a big asset for an experienced programmer. The same way with doctors. Their tools are changing rapidly but the underlying concept is still the same. She may not know about all the new tools but she understands how a heart works, and because of that she can gauge if the new tool is just a 'fad' or will it change how things are done fundamentally. I think every career path has this in some degree or another.