Here's how it breaks down. If you do ROTC, you will owe 8 years no matter what. Here's where the differences lie. If you go Surface Warfare (ships), you will owe four years of active duty starting from the day you graduate college. If you go Subs, you will owe 5 years active duty. The rest of the time can be spent in the reserves. As for Pilots, you will owe 8 years of active duty service from the day you get your wings. So, you will be in the active duty navy for about 10 years before you get the chance to get out. Flight school counts for your pension, but not for obligation time. For NFOs, we owe 6 years after wings. If you have any more questions, don't hessitate to PM me. Good luck. I was a two year guy and don't regret it for a minute.