Is it worth the while when you have to spend more than weeks to do it right later? Again, in general it is not. You are citing a very, very specific business reason as a justification. In 99% of all cases, no good business reason exists to waste more money later. Essentially, this is what you are asking. In your example, it's either 8 weeks total to do it right in the first pass or 10+x weeks total to do it right later when you have the still unquantified extra overhead of not breaking stuff that has been built around the insufficient solution.