I am 61 yrs old, 58, 136-138 lbs. (work out with weights), and wear a Size 4 Regular in Gloria Vanderbilt jeans/leggings. The Rekucci Size 6 is a bit big in the waist and rear for me. I love these pants for tailored gym-to-around town wear, though, and will experiment with sizes. I will try the Slim 6 with belt loops next.