Definitely. "Is it good enough for the business?". If yes, then leave it alone. Try to add new features in a safe way with automated tests.

I once worked a contract where it was expressly forbidden by the dev manager to refactor any code unless it was demonstrably necessary to support a new feature. Not much fun for devs at times but I respect the reasons behind the decision (esp. as it was a derivatives trading platfom and it can get pretty expensive pretty quickly when they go wrong).