A good manager, especially if they can recognize weakness in the existing code base, will let you refactor things. I've quit a job before when I wasn't allowed

A good manager, especially if they can recognize weakness in the existing code base, will let you refactor things. I've quit a job before when I wasn't allowed to rewrite code which actually wasn't even functional. I've been extremely fortunate and that most of my recent managers have been okay with me either completely rewriting the code base, or implementing my own practices. I have no qualms about leaving a job where I'm not able to do my best work.