- one that purchases a commodity or service
Good or bad, that term has a certain "transactional" connotation to it; the retail model is pretty clear: a person goes to a store, buys a product or receives a service, then leaves. You don't have a relationship with the clerk running the point-of-sale system; you get your stuff and go. Transactional.
For gasoline purchases and groceries, this may be the right model and the right term. But is that the right model for you in IT? Consider it instead from the reverse point of view:
What is your relationship with your barber/hair stylist (Some of you reading this might not use one: your tonsorial needs may be non-existent or you may be able to handle things for yourself. But I bet you can probably remember a time when it was a regular requirement...)? Do you have a certain place to which you always return? When you go there, is there a particular person to whom you look (or schedule or wait) because you get a consistently good cut, or because the conversation is more pleasant, or some other (in)tangible benefit? Do you like the personal service that comes with being known by your first name? Would you have a hard time switching to a different barber/stylist because of the trust you've given to your current one? That is the sort of relationship you should seek to have with your...clients.
- one that is under the protection of another : dependent
- a: a person who engages the professional advice or services of another
That, then, pushes a certain level of responsibility on the provider. Be(come) the trusted adviser by not abusing the trust. Provide good advice. Provide repeatably good service and/or products. Own your mistakes and gently guide your client away from making them on their own. This is how one treats his/her clients—especially if the goal is to keep them!
If you're not already in this frame of mind, I challenge you to make this shift in a simple yet subtle way: Even if you're in the "business of selling widgets," even if you're running a convenience store selling gasoline and snack food, train yourself to stop using the word "customer" and start using the word "client" instead. Words have power; they convey ideas and have implications. Changing the use of that one word should change the way you look at the people you serve; when your outlook changes, the way you act and react in the relationship should follow. All of your clientele may not perceive the difference, either overtly or subconsciously; some still want to be "merely" customers, ignoring the relationship and simply needing a widget or two. Making this adjustment won't "fix" that relationship, but neither should it affect your ability to be there to serve them when they choose you. But the shoppers, the fence-sitters? With this one subtle change, you could influence them in a way that sends them into your care with more frequency.
Disclaimer: I currently work for a value-added reseller—a "VAR" in industry parlance—but have also spent a long time as a purchaser of products and services. I believe this concept is valid in either case.