I wear them when I run, 4-10 miles a run. I'm slim and wear size 9.5 men's shoes. The shoes I wear them with are the lightweight, semi-minimal Brooks Pure Cadence 3s. My feet sweat profusely. I love these socks. They have excellent breathability compared to almost every other sock I've worn (at least a dozen different types over the years). There is actually a breeze on my feet and toes. As someone whose feet were literally dripping with sweat, these socks were amazing, they wicked the sweat away from my feet and kept my feet from feeling like they were sinking into my shoes. Even after running in the rain, pairing these socks with my breathable shoes didn't cause any issues like excessive squeezing (from water) or blistering. The ankles are raised high enough to completely cover the area around the Achilles tendon. it sometimes rubs with high-heeled cup shoes, but they only stick out an inch or two from my shoes, so it's not very obvious. The midfoot fit is snug (sure?) but not too tight. They definitely won't give me blisters. Likewise, the heels and ankles are snug enough to feel snug without sacrificing circulation. These are well designed socks. Unlike (many) other synthetic socks I've worn, they don't feel slippery on the inside, so I don't feel the need to over-tighten the laces. Big plus for me. Finally, these socks are so cheap compared to everything else I've tried. The price for 6 packs is the same as single pairs I don't like as much as these. After a dozen runs in my first 6 pack I bought a second pack because I finally found the socks for me.