Pay Off Properties vs Purchase More Properties

[KB Bergeron]

Greetings Everyone!
My name is KB and I am currently serving in the military. I have 2 rentals (one I previously lived in and converted into a rental, and the other purchased as a rental) Question: Does it make sense to put forth as much $$ as possible toward the two rentals...in order to pay them off within the 6yrs of active military service I have remaining....to more effectively (recieve 100% rental income from both rentals) supplement my retirement?? Or should I concentrate on building my portfolio by trying to accumulate more properties. (by saving up for down payment, or by rerfinancing). Your experienced opinions are greatly appreciated. Thanks in advance for your help! :D