Remember those old movies where doctors would show up at a patient’s home for a house call? Almost always, they bring that little bag with them, full of stuff they probably won’t use.

You need a doctor’s bag too — call it your speaker’s bag. Mine is a Lowepro CompuDaypack. I’ve used it for years. It comfortably fits my 17″ MacBook Pro (in a padded space), lots of zippered pockets for business cards (or instant coffee packets), and a self-contained bottom portion great for bulky items like AC power cables. Also, it fits nicely under an airplane seat — a very important criterion.

The most important thing to know about your speaker’s bag is this: Treat it as if it were a real appendage like your arm. Never, ever let it out of your sight. Don’t ever check it in airport security.

Naturally, you’ll want your notebook computer, pens, business cards, etc. in there. Here are other items in my pack that sometimes surprises people:

• Backup dongle: Macs unfortunately don’t have a regular VGA out port; we need a special adapter to get VGA. I have three of them. Yep, three. One in my suitcase, one in my speaker’s bag, and one in my jacket pocket. If I don’t have one of these, I can’t do the presentation. (I also tell the A/V crew to make sure they provide their own, so there’s another level of failsafe.)