The problem I have with opportunistic refactoring, in the context of Scrum at least, is usually the extent of the cleanup is not known until you start making ch

The problem I have with opportunistic refactoring, in the context of Scrum at least, is usually the extent of the cleanup is not known until you start making changes. By that time, you have already given an estimate for the story points. Hopefully, the business considers this a forecast. Unfortunately, many times this is considered a commitment. If you do the refactor, you may miss your commitment, and easily measurable things for the business (your velocity) look bad while something that was not easily measured (tech debt) remains unquantifiable and unchanged either way.