Raise your hands (or maybe not) if you've broken a nail in the past few days. Or noticed that your fingernails are starting to fray and split way too easily. We've got enough snags in our cashmere sweaters and runs up and down our black tights to suggest our nails are anything but smooth. Frustrated with how weak our nails have become and beyond baffled over our manicures barely making it to the five-day mark, we asked three nail pros to spill their secrets on growing strong and healthy nails.