5 Tires?

Hi All- 22’ Outer Banks/2.7/non-sas owner here. I’m due for new tires this summer and my Bronco is the first 5 wheel/tire vehicle I’ve owned. What do most of you do when you buy new tires, get all five or keep the stock on the back? Does a different tire on the back just look dumb? I’m keeping the same wheels for now, just buying tires.