In at least a few places I have violated the DRY (Don't Repeat Yourself) principle. At early stages, this was somewhat deliberate; I would prefer to hold off refactoring code to remove duplication until the code is working up to a point and clear patterns have emerged; otherwise there is a risk of refactoring too early and having to adjust and rebuild again later anyway.
In at least a few places I have violated the DRY (Don't Repeat Yourself) principle. At early stages, this was somewhat deliberate; I would prefer to hold off refactoring code to remove duplication until the code is working up to a point and clear patterns have emerged; otherwise there is a risk of refactoring too early and having to adjust and rebuild again later anyway.