All patents have a set amount of years in which they can offer protection for an inventor, although for the different types of patents this time frame differs.  Utility and plant patents grant a protection term of 20 years from date of filing, while design patents last 14 years from date of issue.   As for the patent process, the time frame between first submittal and final granting of a patent averages around 24.6 months currently.  

Applications are numbered in the order they are received at the U.S. Patent and Trademark Office, and will typically be processed in that exact order in the group art units they are sent to.   An applicant will usually know within eight weeks of filing a patent application by mail what the official filing date and application number of their application is.   Electronically filing a patent will obtain an application number within minutes.