Do you have thorough unit tests for the code that you are trying to refactor? If not, be aware that there is no way to know for sure that your refactoring won't

Do you have thorough unit tests for the code that you are trying to refactor? If not, be aware that there is no way to know for sure that your refactoring won't break the functionality of the code. If there are no unit tests ... the original coder didn't care about correctness, and refactoring towards testability is a good thing. The more people you will need to interact with, the more damage you will do to yourself and your reputation. Others will resent working in panic mode to clean up after you (now widely known as the "rogue" programmer). I'm in two minds about this. Yes, you will need to be careful about not introducing changes, and yes, occasionally fixes will be needed. But better code should be a plus to reputation. If it's not a net plus, be more cautious. If that can't be done, I'd be thinking that I was in the wrong job, and my reputation with those co-workers was irrelevant.