Unless the code is very well covered by unit tests, any refactoring can introduce bugs. If the code is well established and no longer changing, there is no ease

Unless the code is very well covered by unit tests, any refactoring can introduce bugs. If the code is well established and no longer changing, there is no ease of maintenance to be gained. There is only downside to changing it. If the code is causing more work to maintenance and new development, sure it may make sense to refactor it. Otherwise, like the human appendix, just leave it alone until it causes a problem.