I am too self-conscious to leave home in something I find unflattering. And I currently don't own a single pair of real skinny jeans, since they make my thighs/hips look ginormous - you know, the type that narrows down around the ankle. I usually wear boot-cut or flare style.
However, I always have a pair one size too small, which I try on often, or even wear at home - just to see how far am I from actually wearing them. And it doesn't have to be jeans - my current test-pants are nice trousers, which I can in fact squeeze in, but are too tight to operate normally while wearing them.
Side note: I always "admired" bigger girls, wearing skinny jeans. I used to believe that skinny cut was made only in XS/S size, perhaps lower end of M. I buy my jeans in a multi-brand store, due to their great selection of models and washes. So, going there, I saw several plus-sizers wearing skinny jeans and I asked sales lady where on Earth could they find them. Then she showed me some 10+ skinny XL models they have, explaining "I never offered you any of those since I can see that you dress tastefully and didn't want to insult you..."