What fees are involved in Patent Prosecution?

It usually takes 15-24 months to hear from the Patent Office once an application is filed. At that point, we would expect to get the Office Action (or rarely, a notice of allowance). There is a cost to review the office action in which time we read the office action, review the cited references, and prepare a plan for response. In reviewing the office action we write you a letter which includes the cost to respond to the office action. It usually takes 3-5 hours to respond to an office action but we do most of our patent prosecution work on a flat fee, quoted in advance. Once an application is allowed the government charges an issue fee and we charge a fee handle payment of the issue fee as well as review the patent for accuracy. Lastly as previous explained maintenance fees are charged at 3.5 years, 7.5 years, and 11.5 years after the issue date of the patent to keep the patent alive and we charge a fee to handle maintenance fees.