What is the longest you can stay in the Navy?
On 1 August 2017, the U.S. Navy extended the HYT for active component sailors to 10 years from 8 years for third class petty officers, to 16 years from 14 years for second class petty officers, and to 22 years from 20 years for first class petty officers.
High Year of Tenure - Wikipedia
https://en.wikipedia.org/wiki/High_Year_of_Tenure