This is a guest post from Stephen A. Smith.

When I was hired as a sales clerk in a record store, my boss said something to me that I’ll never forget. “Nobody has ever been fired from this company for being too lenient with a customer.” Not every manager has the wisdom to tell his employees that fact, but it’s generally true throughout the retail industry. Hence, the controlling principle of customer service: The squeaking wheel gets the grease.

If you want something, ask. I’m not suggesting that you haggle over a gallon of milk, but you can almost always convince a company to acquiesce to any reasonable request if you remember two words: “polite pest.”

You’d be surprised how many fees can be waived simply for the asking. For example, most credit card companies have a policy that allows their representatives to waive one late fee per account per year. Late fees are a coup for credit card companies, and they won’t waive one automatically; but if you pick up the telephone and ask, you can save yourself $35.

Banks often have similar policies regarding overdraft charges. Your cable company may have a promotional discount available that a representative would be willing to apply to your account. Verizon agreed to reduce my rate when I pointed out how infrequently I used my cell phone. For years, AOL was notorious for assigning six months’ free service to any subscriber who threatened to cancel; all you had to do was pick up the telephone twice a year and you had AOL free, forever. Like someone said: “You’d be surprised what all you can get if you ask for it the right way.”

My favorite tactic is to mail letters. I’m a strong advocate for voting with your wallet, but that doesn’t mean you have to remain silent. I write letters when I get great service. I write letters when I get terrible service. I write letters when I think a policy needs to be changed. And the only thing more surprising than the number of companies who never reply is the number of companies who mail me gift certificates. It’s basically alchemy: Invest 10 minutes of your time and you can turn a 37-cent stamp into a $50 gift certificate.

In the restaurant industry, this bell rings even louder. Think of your waitress as your lawyer: She gets paid $2.39 an hour without tips, so she wants you to be happy. If your request is polite and reasonable, she’ll sell it to her boss. If your dinner goes well, then by all means, pay full price — but too often, when the kitchen makes a serious mistake, the bill goes uncontested. In most restaurants, it’s standard operating procedure to offer free dessert when a mistake disrupts someone’s dinner — sometimes, you just have to ask.

Don’t be afraid of appearing to be a cheapskate. Yes, there are people who demand unreasonable discounts and try to negotiate the price of DVDs with sales clerks. But these tactics are like personal injury lawsuits: Just because some people abuse them, doesn’t invalidate the fact that they exist for good reason. Companies know this. They can usually tell the difference between a legitimate customer and a scam artist — and when they can’t, they will usually err in your favor.

In jurisprudence, we subscribe to the notion that it’s better to let five guilty men go free than to wrongfully imprison one innocent man. By the same token, I don’t want to write a column suggesting that everyone run out looking for freebies; but I think it’s worse when customers silently seethe instead of speaking up for themselves. If you take a polite request far enough up the ladder, even the corporate monoliths will eventually fold. Be an active consumer. Squeak.

This article is about Odds and Ends