(Photo: Davies and Starr)

Eat If You’re Dieting
Before work. “Breakfast eaters manage their weight better,” says NYU Medical Center nutritionist Samantha Heller. Skip it and you’ll be ravenous and likely to overeat by lunchtime.

Get Your Picture Taken
Around noon, says photographer Timothy Greenfield-Sanders in Michael Kaplan’s The Best Time to Do Everything. In the morning, the side of your face you slept on is still puffy. In the afternoon, tiredness starts to show.

Get a Last-Minute Restaurant Reservation
Call the day before you want to go, around lunchtime. That’s when many people call to confirm or cancel dinner for the next evening, and open tables are more likely.

Get Through to Time Warner
Call between 1 and 5 p.m. any day (except Saturday)—that’s when the the cable service’s help hotline (212-358-0900) has its lowest call volume.

Buy Shoes at Bergdorf Goodman
At 10 A.M., opening time, when the salesperson-to-customer ratio is lowest. Feet swell over the course of the day, though, so be careful if you pick a tight-fitting shoe.

Leave New York
If you want to avoid long security lines, leave JFK and La Guardia between 10 a.m. and 2 p.m., when they’re least busy.

Retain Information
Between four and five in the afternoon, according to studies that show that’s when college students are most attentive. It varies as you age, though: For over-sixties, early morning is best.

Look For an Apartment
In the daytime, to gauge light, sure. But don’t forget night: Important features like neighborhood noise level vary throughout the day, so you have to go back at different times to make a smart choice.