Eric said, " But how long does Polypropylene last?
I am not sure what Polypropylene fencing is.
When we moved here in May 2013 we used a couple of plastic fencing for different purposes. One was an orange fencing about 4 or 5 feet tall. It was originally used as a dog pen which did not work well so it has spent the last 10 years protecting honeysuckle.
Then we had some sort of black mesh the same 4 or 5 feet tall with 1" squares to protect blackberries from birds. It is still going strong though it needs to be removed because a vitex now occupies the space instead of blackberries. I know it is over 10 years old.
My fencing was made over 10 years ago so the quality could be entirely different.
If I was in your position I would probably make a rosemary hedge all along that fence. It is easy to propagate so only a few plants might be needed. My theory is that the deer will smell the rosemary and say no thank you.