You've finally gotten into a style groove. You know what looks good and even have some killer go-to looks — but then, your life changes. You’ve nabbed the big job, had the first (or second) baby, entered a new decade — and suddenly, the clothes you once rocked just don't seem to rock quite as much anymore. That flared skirt silhouette looks too young. Ditto on the girly prints and too-low skinny jeans that just aren’t channeling that glamour vibe you're craving. Suddenly, after a milestone (or many) you have to suss out a wardrobe that works for the playground, the big meeting, or your 40th birthday party.So, how exactly do you navigate these big life transitions, with really great style on your side? We've asked three sartorial gurus — Glamour’s fashion market director, Sarah Meikle, Barneys New York's Creative Ambassador at Large, Simon Doonan, and super stylist, Annabel Tollman — for advice on how to stay current through life’s iconic moments.