Q I am traveling on a Sunday and don’t have a printer at home. How far ahead can I print out my boarding pass? I’d like to be able to do that from work on Friday.

A Sadly, you won’t be able to use your employer’s printer paper for your boarding pass. Flyers may begin checking in online — and printing boarding passes — 24 hours before a flight, but not before, because that’s when airlines release free seats.
There is another, paperless, way to check-in from home. Mobile check-in is an option for anyone with a smart phone or other PDA. You supply your mobile e-mail address or your cell phone number, along with your reservation number, and voila: your boarding pass is sent to your device. As with online check-in, you can take advantage of this within 24 hours of your flight.
If neither of these work, my advice to you: arrive at the airport 75 minutes before a domestic flight. Airplanes have tended to be full this summer and it’s often those who fail to check-in on time that get the boot.