Almost never. I was an enthusiastic embracer of OO when I started with Python because it was pretty much the sanest way to manage state in that language. But t

Almost never. I was an enthusiastic embracer of OO when I started with Python because it was pretty much the sanest way to manage state in that language. But truth be told, once I moved to Lisps and FP languages I scarcely bothered to touch them. If you're not handling mutable state at all, then an object that primarily exists to carry mutable state is of limited utility. I did write an object-like system in Heresy, but I've yet to make much serious use out of it; it was largely an academic exercise.