It all depends on what your doing and what the temp is. I ride out west and find that I am always warm do to the fact that the type of riding I do so I where the thin polaris one then. If it is colder and windy I switch to the klim it keeps my neck warmer. If you get to warm you perspire and that leads to fogged goggles so try a few things till you find what works for you. I also use the HJC universal breath guard in my helmet it's painless and keeps your breath from fogging up your goggles. I stay away from the no fogs and what not due to the fact that I have a system that works for me. You will figure it out with a little trial and error. I now use 1 set of goggles all day unless its precipitating then some times switch to the backups if needed.