Must have vents
The vents should be standard...You will never look back at the other standard vents.
I would install them for the simple reason of being able to generate fresh air in the Summer while not using the trailer. Think about how hot your trailer can get inside, the odor's, humidity etc... the Vents help promote air flow which in turn will give longevity to the wall paper on the walls to the carpet staying fresh. It always shocks me that they keep them reasonably priced...
Top 5 affordable upgrade in my book...
2011 JAYCO JAYFLIGHT G2 Rl