There are do-all mascaras that promise thick, defined, mile-long lashes with the swipe of a wand—but experts say that these aren't the way to go. A single tube can pack only so many effective ingredients, and formulas usually have to sacrifice one benefit for another. "If you want a specific effect, look for a specialized type," says makeup artist Troy Surratt. The resins and waxes in a curling mascara lift and bend stick-straight lashes, while a lengthening formula's nylon fibers act as extensions on short ones. And the brush matters, too: If it's big and bushy, that's how your lashes will look. A brush with spiky plastic bristles separates.