Have been lucky all jeans that fit are a Size 4 SHORT/petite (5'1") in all brands. Being short I like the straight narrow legs they my legs look longer than they really are & also work easier with boots. Also like the ones that come just below my waist (natural waist?). Also like mid rise so when I tuck in my shirts it gives a much flatter look. Material also has to be stretchy because after washing the need for them to stretch is great.
I wear some elastic waist legging colored jean material pants for when I wear outside tops & want to match colors with the pants.
I was given a pair of leggings for Christmas. I looked at the size & it was a 0

I thought why bother even trying it on but I did. They fit perfect & are my most comfortable leggings, I went out & bought more, some in the denim look. That was definitely an ego boost when they fit since I try even at my age to stay in good shape