At a previous job, we hired a fair number of both junior and senior engineers. The job was doing F# and since most places don't do a ton of functional programm

At a previous job, we hired a fair number of both junior and senior engineers. The job was doing F# and since most places don't do a ton of functional programming, I would try and get people up to speed in some of the more functional aspects of the language (how good I was at that is a matter of opinion). I always enjoyed teaching the junior engineers more, simply because they hadn't developed a lot of habits yet, and their brains were more plastic. Instead of trying to "write Java in F#", it was easier to just teach them idiomatic F#. Senior engineers were more annoying, because they were kind of "too good". Instead of making a real effort to try and learn the language and its quirks, they would instead just try and figure out ways to do their old imperative stuff in F# (e.g. using `mutable` everywhere, using classes for everything, relying on state instead of function arguments, not really utilizing monads, etc.). Most of them did eventually pick up F# and got reasonably good at it, but it was always harder to sell them on it. I think it's good to have a mix of both. Senior engineers come in with a lot of expertise and can often think about projects at a higher level, and that has obvious value, but I think they can also develop tunnel vision and get fixed in their ways [1]. Junior engineers can look at things with fresh eyes, and give new perspectives on things that can sometimes be non obvious. I also think mentoring is good for senior engineers as well. It's extremely easy to become jaded with industry. Corporations are uncaring monsters that kind of objectively suck ass, and it can easily make someone extremely cynical over the course of several years. I think there's a lot of value in having exposure to people that haven't had the life and hope drained out of them yet. While I'm not planning on doing it again for the foreseeable future, I did enjoy teaching at a university for two semesters, and I particularly enjoyed talking to the ambitious students who really took school seriously. I'd like to think I made a positive impact on them and helped them grow their futures but of course it's impossible to really know that. [1] I'm certainly guilty of that, though I do my best to try and fight it.