It's basically only done when something goes wrong, IME. All but the most recent history exists mainly for git-bisect and being able to branch historical versions to patch some old release-in-the-wild (if you're developing on the Web with a modern release-often style, the latter may rarely happen for, as you write, "a commit more than a sprint or two old", but it's common on software with longer release cycles or long-supported older versions)