I am a woman in my 60s who has problems with swelling in ankles & feet. My doctors recommended compression socks, which I was not happy about until I discovered these. The 15-20 mmhg works for me. I don't have to worry about shoes that fit in the morning and then are painfully tight later in the day. I also tried 20-30 mmhg compression socks, but they were difficult to get on and I didn't see much more of a difference. I have ordered 2 additional sets of these because I love them! Highly recommend.