Ms. Fernandez currently favors Céline, a brand whose designer, Phoebe Philo, has a pants track record that goes back a decade to her time as the creative force behind Chloé. In 2010, Ms. Philo launched a capsule collection of Céline's "Five Perfect Trousers" that were available in various fabrications. (The quintet was eventually folded into the brand's general collection.) If you're looking to invest in a beautiful pair, Ms. Philo's latest offerings, which come tapered and slung low on the hips, as well as high-waisted and Katharine Hepburn-esque, may be the way to go.