Time spent early in the software production cycle can lead to greater economy at later stages. It has been shown that a bug found in the early stages (such as requirements specification or design) is cheaper in terms of money, effort and time, to fix than the same bug found later on in the process. Requirements defect that is left undetected until construction or maintenance will cost 50 to 200 times as much to fix as it would have cost to fix at requirements time to take an extreme example, if a program design turns out to be impossible to implement, it is easier to fix the design at the design stage than to realize months later, when program components are being integrated, that all the work done so far has to be scrapped because of a broken design.