If yours are yellow, brittle, or thick, see a podiatrist. According to New York City podiatrist Krista Archer, DPM, all are signs of—forgive us for mentioning it—fungus. Your doctor can prescribe medicine to penetrate the nail plate and clear up the offending condition, but you'll still have to wait for the nail to grow out (typically six months to a year). So it's better to start treatment sooner rather than later.
Get in shape
New York City nail expert Jin Soon Choi recommends filing toenails in a foot-flattering square shape with rounded edges. If you're prone to ingrowns, however, stick to straight-up square.
Be a softie
To stave off cracked heels and calluses, buff weekly with a foot file, suggests Choi. "For maintenance, use a pumice stone in the shower every day," she says. "Follow that with foot cream once you get out."
Sweat doesn't exactly leave your feet pleasantly scented. "Bacteria and fungus go hand in hand with perspiration," says Archer. If odor is an issue, spray the soles of your feet with an antiperspirant-deodorant and dust the insides of your shoes with a light coating of antifungal powder.
To help release tension, give yourself a mini-massage the next time you're moisturizing. Wil Lewis, the national massage therapy trainer at Exhale spas, offers a three-point plan: Start by fanning out your toes with your fingers to help relax feet that have been squished in shoes. Then twist your arches—to the left, to the right, up, and down. Finally, knead your soles right in front of the heel bone.
And, of course, add a splash of color with a bright, playful polish, like Nars Nail Polish in Libertango ($19; NarsCosmetics.com).