Open-source software licenses are intensely boring things to read about. The choice available makes it very easy to default to not organising a license. Particularly when you are a serial procrastinator like me!
However I would love for others to use my codes. It’s why I wrote them. So I sat down for a concerted half hour reading. My personal bias having benefited so much from GNU software would be for the GPL. But as the codes I write are relatively simple, they are likely to be incorporated into other larger packages, rather than be forked and developed as is. The MIT license therefore seems to provide a minimal-touch mechanism, and guarantees that all important (for an academic) aspect of attribution.
This is GPL compatible, which I hadn’t really thought about as being a necessity. So in the future, if I ever build something complete enough that I would worry about a commercial entity forking it & producing a closed-source derivative work, I could license that under the GPL yet pull in all of my prior work.
Here was the most succinct article on this issue I found: