Patent application prosecution is dependent upon the complexity of the rejection, the reasonableness of the Examiner, the closeness of the prior art as compared to the scope of patent protection desired by applicant, and the quality of the applicant's comments for responding to the Examiner. The period of prosecution, and the interval over which these added costs are incurred, averages one to two years.
After allowance, and upon payment of issuance fees, the application issues into a patent.