Mark Di Vincenzo, founder of the Business Writers Group, gets into the nitty-gritty of why timing really is everything with his book "Buy Ketchup in May and Fly Before Noon" ($13.99; Watermark Books). The collection is about 170 pages of tips on when it's best to do just about anything.
Best time of day to fly: noon. According to airline pilots, you will avoid the rush hours and minimize foul-weather delays.
Best day of the week to fly: Saturday. Airlines have fewer flights on Saturdays, meaning shorter lines, fewer delays. I can vouch for this one. I have flown on Saturdays several times and was stunned by how empty the airports were.
Best month to fly for summer vacation: August. No one knows why, but there are fewer flight delays than in June or July.
Best day of the week to shop for airline tickets: Monday or Tuesday, when airlines roll out the best deals.
Best day of the week to rent a car: Tuesday or Wednesday. Most business travelers already have their cars, and you will beat the rush by city dwellers who want a car for the weekend.
Best day of the week for a hotel upgrade: Sunday or Monday, the slowest days of the week.
Best month to book a cruise: April or November. That is when you can catch their repositioning cruises. The drawback is that these often aren’t trips with many port calls.