This has been addressed so many times in the past, but here we go again.
I'm sure there are places with more deer than here in the middle of Missery, but we have enough to be a decent test. I have fenced my garden for the last 6-7 years with 52" cattle panels. The deer would jump that easily, so I attach a pvc extension to every other other t-post and run something they can see as high as I can reach. I've used nylon cord with things tied to it, like plastic grocery bags. Lately I've used the plastic marking tape instead of the cord. It comes in lots of colors, but yellow seems to be the cheapest. We've had some miserable dry years in the period I've had my garden fenced this way, but I have never had a deer jump through my "barrier". Could they? Sure they could. If they were desperate enough I'm sure they would, but maybe I just have calm deer.
Chuck