title: When should you not refactor?
body: <p>We all know that refactoring is good and I love it as much as the next guy, but do you have real cases where is better <em>not</em> to refactor ? </p>
  
  <p>Something like time critical stuff or synchronization? Technical or human reasons are equally welcome. Real cases scenarios and experiences a plus.</p>
  
  <p><em>Edit</em> : from the answers thus far, it looks like the only reason not to refactor is money. My question is mostly relative to something like this: suppose you would like to perform "extract method", but if you add the additional function call, you will make the code slightly less faster and hinder a very strict synchronization. Just to give you an idea of what I mean.</p>
  
  <p>Another reason I sometimes heard is that "others used to the current code layout will get annoyed by your changes". Of course, I doubt this is a good reason.</p>