Updated and adapted from the book "1,001 Things They Won't Tell You: An Insider's Guide to Spending, Saving, and Living Wisely," by Jonathan Dahl and the editors of SmartMoney.

1. "We're as good as our word. And that's not very good."

   It used to be that hiring someone to clean your home was strictly for the super-wealthy. But over the years, as more women have entered the workplace, the practice has become commonplace even among middle-class households. Bill Griffin, president of Cleaning Consultant Services, a Seattle firm, also cites more recent trends for the growth of the industry, including increased concern over microbes and infectious diseases such as the swine flu. Today, there are an estimated 30,000 cleaning-service companies out there, ranging from self-employed housekeepers to nationally franchised chains. Unfortunately, there's no way of knowing what you'll get until it's too late, since anyone "with a spray bottle, rag, and business card" can call himself a housecleaner, Griffin says.

   How to vet prospective services before hiring someone to clean your home? Before pulling the trigger, ask for five references from customers who have used the service for at least six months.

2. "We're more about a quick clean than a thorough job . . ."

   In an effort to hit several houses in one day, many housekeepers move through homes like whirling dervishes. That can lead to inattention to detail, loss of property-or just substandard cleaning. While service standards vary widely, all firms should promise a reasonably detailed checklist: That means wiping down every surface in the bathroom, for example, including scrubbing the tub, toilet, and sink, as well as cleaning the bathroom counters and mopping the floor with cleaners. Also, to ensure those standards are kept, ask for employees who have been with a company for at least six months. Because housecleaning is a transient business, staff turnover tends to be pretty high, according to Griffin.

3. ". . . that is, if our workers even know what they're doing."

   As president of M-Squared Public Relations, a boutique public relations firm, Marsha Middleton works a 60-hour week. To reduce her hassles at home, Middleton has begun using a cleaning service. But in one year, she says she's gone through five cleaners. One swore she could iron, Middleton says, but "when I said, ?This is what needs to be ironed,' she started shaking like a leaf." The maid admitted to her that she lied to get the job and was planning to call over her brother as soon as Middleton left.

   While it may seem like an obvious prerequisite, not everyone in housecleaning has real skills. Before you sign on with an agency, you should ask what kind of training it offers employees. At Ann Arbor, Mich. based international chain Molly Maid, for example, new employees go through a one-week training class, then an average of four days practicing in "test" homes before they start working with clients.

4. "The first time's going to cost you."

   The average price range for a service to clean a four-bedroom, three-bath home every two weeks is $80 to $170, according to industry experts. However, if you've never used a service before, an agency may insist on an initial "deep-clean" of your house. That can mean wiping down the inside of a refrigerator instead of just the handle, or moving a couch to vacuum underneath it-all of which can jack up the price for the initial job by two to three times the typical fee.

   For some companies, though, the initial fee is just a ploy. Such cleanings can run upwards of $300, says Griffin, if companies think that's the only time you'll be using their service. It's perfectly fine to request to skip the preliminary deep-clean and go straight to the standard service. If an agency balks at that request, Griffin says, you're better off eliminating it from your list of prospective cleaners. Plus, once you're using the service, don't shrug it off if you come home to find that a sub-par job was done. The key here is to speak up fast-many agencies will revisit a home the same day but may excuse their sloppy cleaning as the dirt that's accumulated in your house over the past 24 hours.

5. "You're letting a bunch of strangers in your house, you know."

   Consumers typically leave their key-and their otherwise unoccupied home-in the hands of trusted housekeepers on the day of a scheduled cleaning. How can you feel comfortable about who's entering your home? First, make sure the agency has cross-checked a worker's documentation to verify his or her true identity. Then, at a minimum, confirm that the company runs background checks to look for felony and misdemeanor convictions for the past seven years. It also helps if an agency reviews each applicant's credit history, as well as prior employment and previous judgments against him or her.

   Contact your state's attorney general to ask what kind of background checks are available in your state. Some have their own bureau of criminal identification, which can run checks for a small fee, but the subject of a check must consent first.

6. "We're bonded-for what that's worth."

   Background checks notwithstanding, in the event that a housekeeper steals from you, you're likely to see little or no reimbursement for your loss. If no one is arrested, it's a cleaning-service employee's word against yours.

   What to do, then, if something disappears and you feel certain that it was stolen? Your best bet is to file a police report immediately in order to start the process early. A good preemptive defense, beyond background checks, is to give preference to companies that use cleaning "teams," in which two to four cleaners, including one supervisor, come to your home at the same time to divide tasks. Not only does that make your cleaning more time-efficient, but also, employees are less likely to steal or be careless under a supervisor's watchful eye.

7. "Sorry, that doesn't quite translate."

   Language barriers can create issues between homeowners and their non-English speaking housekeepers-from cleaning errors to shrunken laundry items. Short of hiring a translator, you can request an English-speaking maid from the service you're using, but getting one may not always be easy, since the majority of workers in the housekeeping industry today are immigrants-as much as 60 percent just at Molly Maid alone. Indeed, it's another good reason to use companies that clean in teams, where at least one person speaks English fluently. Another good tactic: Call the service with special requests the night before, and have supervisors relay them to its housekeepers before they arrive at your home the next day.

8. "Sure, I'll work under the table-but you're the one who pays if we get caught."

   It's tempting to slash your cleaning costs by forgoing the bigger cleaning services and hiring a self-employed housekeeper. Indeed, self-employed cleaners typically charge roughly $10 to $25 an hour- pretty cheap compared with the big or franchised services.

   Of course, the easy way out is to pay a maid in cash under the table, which many people do. But if you get caught, you'll likely owe the IRS back taxes, and if you've knowingly employed an illegal worker, you could face steep penalties. On the other hand, if you use a service that hires maids illegally, penalties will fall on its shoulders and not yours.

9. "If I get hurt in your house, we'll both be in pain."

   Homeowner's insurance policies cover some, but not all, workers who enter your home. You could tack on an umbrella policy to your existing homeowner's plan, but some don't kick in until your losses are high-say, $300,000 on a $1 million policy.

   If you have a cleaner who comes regularly and doesn't work just for you, make sure to get a written agreement that states she's an independent contractor and that you are not responsible for her taxes, Social Security, or workers' compensation insurance. It's safer, however, to use a service that carries a few key forms of insurance. For starters, look for general liability, which covers damage to a home or homeowner and typically ranges from $300,000 to $2 million. Most important, though, is making sure the service has workers' compensation, which covers any injuries a worker may sustain while on your property and pays for lost wages so that an employee won't be tempted to sue you.

10. "We don't always make up for our mistakes."

    Mistakes can happen, but when a housekeeper accidentally ruins your marble countertop with the wrong cleaning agent or breaks a prized piece of china, you will want to be made whole. While larger companies are likely to pay for seemingly minor damage-say, broken dishes-they are often technically able to absolve themselves of responsibility for franchisees if they choose to do so.

    While you can always sue a company, it's easier and cheaper to try mediation first and then arbitration. You can call on the Better Business Bureau. You can find a bureau near you at www.bbb.org.