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Some languages on the jvm (namely scala) do have tail call recursion, meaning that in many cases recursion can use constant stack space

I thought you had to manually mark the method (and/or the recur site) for scala to do tail call optimisations.

It does the optimization by default, the annotation is to ensure it raises a compilation error if it actually fails to optimize.

Indeed, and it should be noted that it's quite limited in when it can actually apply the optimization, i.e. self-recursion only (I believe).

I think a useful litmus test is to consider the worst-case depth of whatever you're building. I often feel safer writing my own userland stack, even for stuff like DFS in an interview.

You can't always know how much of the implementation stack will already be used by whatever calls your code, after all. It's a weird kind of "shared resource".

Most languages don't limit stack size at the language level, but at the impl. This is true for Java and for C++.