Some of the benefit to me is “knowing how” rather than “knowing what”. Maybe the hardest thing I did more than 10 years ago that’s unrelated to what I do now was write a MIDI encoder/decoder. I couldn’t write one right now—in fact, I’ve completely forgotten all the important details of the MIDI specifications. But I could write one in a couple days, way easier than the first time, because I know more or less what I did the first time, and I tautologically got lots of practice in the sub-skills that were used the most, even if I don’t remember the details.
So it really does depend on what I want to use the knowledge for.
Some of the benefit to me is “knowing how” rather than “knowing what”. Maybe the hardest thing I did more than 10 years ago that’s unrelated to what I do now was write a MIDI encoder/decoder. I couldn’t write one right now—in fact, I’ve completely forgotten all the important details of the MIDI specifications. But I could write one in a couple days, way easier than the first time, because I know more or less what I did the first time, and I tautologically got lots of practice in the sub-skills that were used the most, even if I don’t remember the details.
So it really does depend on what I want to use the knowledge for.