I love these. I typically buy one size down from what my leg measures. Be sure to measure the area of your leg most affected by friction. I have purchased both the black lace (which I wear under shorts) and the nude unisex style (which I wear with dresses). Mine have always stayed in place very well, but if they get nudged (like when you pull your shorts down in the bathroom) sometimes they take a few adjustments to stay in place. They have lasted all day in 90+ with 98% humidity.