Sometimes true wisdom is just realizing what you DON'T know. (And humility follows closely behind.)

I have never used recursive SPs. I can't think of situation where I might, given the environment in which I am. However, I absolutely love recursive CTE's, even if I could only use them for BOM (bill of materials) explosions. We had a previous implementation that used CURSORS to do them!

I have also used recursive functions. They are handy for string parsing. I imagine that recursive CTE's would do a bit better performance wise, but I find it easier to write readable/maintainable code when done as a function.

Thanks to OP for question!