Code you wrote yourself, especially generic libraries will always be useful for you as long as you use it on a periodic basis. I have some C++ code I wrote back

Code you wrote yourself, especially generic libraries will always be useful for you as long as you use it on a periodic basis. I have some C++ code I wrote back when I was 13 in my first courses in college which is part of my current startup codebase. The question is would these tools be useful for someone else? Would these utilities make other programmers more productive? Would someone pay you to buy your code? (except for its didactic/historic/collector value) I see "On LISP" goes for about 200$ on Amazon despite the fact that you published it as a free pdf.