If you have experience and follow best practices, you should produce decent quality code in the same amount of time as producing bad quality code. In those cas

If you have experience and follow best practices, you should produce decent quality code in the same amount of time as producing bad quality code. In those cases, the gains from improving the code further are not always worth the costs since you should already be taking care of the low hanging fruit. There are always more you can do, but often times good enough is good enough. It is often worth it for inexperienced developers to spend more time refactoring their code though. Besides the obvious improvements to the code base, it helps them gain the skills to do it "good enough" the first time.