This possibly be true in some case, but I find it to mostly be wrong. The best time to fix up some code is when you are already modifying it, because that’s when you are already fully in context to understand the effects. Going back later to clean stuff up is much less likely, because you have to pay that marginal comprehension cost again and again for each issue you fix (and are less likely to even notice the problem). If you’re making this excuse, that suggests you have internalized that it’s ok to makes your codebase worse and you are probably degrading it progressively.