Julie Ziemelis, a Silicon Valley real estate industry public relations and marketing expert, along with her husband Eric, a furniture designer, managed rental properties in Los Gatos and Sunnyvale—until they decided on a job-related stint in Hawaii.

The hope now is that they can concentrate on the venture and leave the property managing to the professionals.

John M. Jenello, a San Jose-based CPA is a nice guy who too often fell for the personal stories of doe-eyed prospective tenants seeking to rent his single-family home rental property.

The busy professional doesn't have the time to keep up with changing market conditions that dictate where he should set the rent. And, when a tenant became a problem Jenello really lost control—until he hired a property manger.

"The bottom line is that for the fee they charge, a good property manager allows you to not worry at all about your rental properties," Jenello said.

The second-home boom has spawned a growing number of buyers who buy or turn properties into rentals, full or part time, and seek to maximize their cash flow by cutting out the middle man—the property manager.

It isn't impossible. Investment property owners all across the nation successfully manage their own properties; they make a profit; they find good tenants and, when a tenant goes bad, they know how to take off the kid gloves. Generally, do-it-yourself property managers rent out only one or two properties; they have some business management background or experience; they learn on the go and they tend to be a little lucky—or they are endowed with a high level of grit.

Doing it yourself to save the 6 percent to 10 percent property management commission for conventional long-term rental properties or the even greater 30 percent to 50 percent or more property management fees on resort and vacation area rentals, can end up costing you more than you sought to save.

There's a lot to learn from existing do-it-yourself property managers who most often turn and run for help when they get what they think is a good tenant who goes bad.

"It's usually to the point they need to get the tenant out and don't know how and out of sheer frustration they hire a property manager," said Sandy Adams, owner of Sandy Adams & Associates Property Management in San Jose.

"People behave on an emotional level and approve tenants who seem like nice people. One client said the tenant hadn't paid since she moved in, and when we checked their application the information didn't jibe and we discovered the tenant was a professional at this sort of thing," said Adams, an industry spokeswoman and president of the Silicon Valley chapter to the National Association of Residential Property Mangers (NARPM), headquartered in San Jose.

Adams says tenants prey upon property owners who aren't trade professionals because they know most of them don't have access to all the background checking services that professional managers do.

In California, professional property managers are licensed by the Department of Real Estate as real estate brokers or as a property manager working under a licensed property management broker, just as real estate sales people are licensed to work under licensed brokers. Like other professional licenses, the shingle comes with educational requirements.

Licensed professionals also should be insured against liability to keep the property owner's liability risk at a minimum. Many of them are also affiliated with trade groups like NARPM and local apartment associations and other trade groups.

In addition to thoroughly screening tenants, property managers have at their beck and call vendors to help them quickly perform a host of maintenance, repair and upkeep chores.

"You can also use the analogy of stock investing. Many investors use a full service broker because the experts are better at managing the investments than are the investors. And in the long run, the investor makes more money even though they have to pay the fees," said Terry Feinberg, who commutes from Gilroy to serve as vice president of the Arizona Multihousing Association in Phoenix.

The rental industry is also heavily regulated by local, state and federal laws that give both tenants and landlords rights, but with those rights come responsibilities. Responsibilities ignored are lawsuits waiting to be filed.

The average investor isn't going to know all the laws and failure to comply can be very expensive, even when found innocent, due to the expense of legal discovery and defense. A fair housing investigation can easily cost $25,000 and that's just for defense, let alone if somebody has to pay penalties, Feinberg said.

"Physically, if you live here and buy a property in Arizona, it's almost impossible to manage it from long distance, especially if it's a vacation rental with frequent guests," said Louis Melo, president and broker of Atlantis Properties in Los Gatos.

Real estate writer Broderick Perkins, executive editor of San Jose-based DeadlineNews.Com, writes regularly for this newspaper.