I retired at 20 to make my way in my civilian tech career. I looked at the amount of effort you'd need to put into make Captain or above, and the knock-on effects on your civilian career, and said "nope." Tried to do the best I could. One of the best officers I worked with in the reserve dropped on request from helo training due to family issues, and ended up making a career as a support guy for the reserve Naval Special Warfare folks.