Keeping your appointments is about more than keeping up appearances.

I've run six marathons and look forward to running many more. But even for those who've never crossed a 26.2-mile finish line, running around is a way of life. As we dash from meeting to meeting or drop the kids off at soccer games and ballet practices, most of us operate at high speed all day long, barely catching a breath until the day is finally through. And for that reason, when I suddenly find myself with spare time because someone has canceled business or social plans at the last-minute, my reaction is perhaps a surprising one. Typically, I'm thrilled. What may be a breach of business etiquette on the part of the cancelling party is cause for me to rejoice. It's an unexpected gift to have a spare hour or two in my schedule, one that operates at breakneck speed. Time to breathe. Time for me. Time to relax. Time to ponder.

And yet, for others, a last-minute cancellation is something to dread.

I have many friends in the service industries—from massage therapists to hair stylists, math tutors to personal trainers. For these individuals, each of whom hustles for every bit of business earned, time is money. A canceled appointment—particularly when the notice is short—has financial repercussions. They have set aside a block of time to work with a client, turning away others who might later request that same slot. In the same way a party host prepares her home for guests, service providers have prepared, too—whether putting together a fun lesson plan or gathering the essential oils their customer favors during a massage. And then, like a slap in the face, a cancellation. Or worse still, a no-show.

Even if the provider's place of work has a cancellation policy, no one wins when it's exercised. The client will typically resent paying for a service not received; the provider worries about the risk of losing the client as a result of that resentment. And of course, the tips that are the lifeblood of a provider's paycheck are notably absent from any cancellation fee.

Life happens. From horrendous traffic jams to sick kids, work obligations to unexpected free theater tickets, there are many reasons—valid and otherwise—why we might not be able to keep our appointments with a service provider. And yet, we owe it to the individuals who have dedicated their careers to improving the lives of others to afford them common courtesy when we need to cancel.

With that in mind, the following are some guidelines for canceling:

•Avoid the temptation to bail if your reason is discretionary (e.g., you're tired and don't feel like it). Remember no one likes a flake—even one who doesn't mind paying a cancellation charge. Honor your commitment to being where you're supposed to be, when you're supposed to be there.

•Cancel (when you must) as soon as you possibly can. Waiting to do so because you're dreading making the call wastes valuable time the practitioner could be using to line up another client to take your place.

•Ensure your notification gets through. Leaving a message on a machine after-hours is fine if that's the first opportunity you have, but follow-up your message with a call to a live receptionist once the business opens the next day.

•If the cancellation is last-minute, offer to pay for the cost of the service. Even if the establishment does not charge for skipped appointments, you'll be demonstrating your respect for the professional's time. Most likely, they will decline. Nonetheless, you'll have proven yourself the bigger person for making the offer.

•Apologize to your service provider the next time you go for an appointment. A brief apology and a bit of extra tip to acknowledge their hardship will go a long way.