My horses both wear fly sheets during the day and go without at night. They both have the Amigo brand - one has the cheapie Amigo Mio Fly Rug and one has the slightly pricier regular Amigo Fly Rug. I like them both a lot! We had daytime temps in the low 90's last week with high humidity and neither horse broke a sweat. Neither one has had an issue with rubs either. As far as fly sheets go, these were pretty inexpensive but have held up great! 2 summers in and still going strong. My horses are both pretty easy on their sheets though, they may roll in them once in a while but neither horse is very rambunctious. I would never NOT put my mare in a fly sheet - she gets awful welts from bug bites and the sheet has completely stopped that issue.