Real-estate agents use a process called comparative market analysis, or CMA, to help home-sellers determine a realistic asking price, and although their less formal evaluations are not accepted by banks, an experienced agent can come very close to a property's true market value.

Most real-estate agents have access to the records of a multiple listing service, which provides a history of recently sold properties that can be compared to the subject property. Agents who work with many buyers have an even greater advantage — they have shown those properties and have a personal knowledge of their conditions, making comparisons easier and more accurate.

You may not always want to work with a real-estate agent, but since a larger percentage of properties are listed with agencies than sold by owners, it makes sense for you to find at least one real-estate agent you trust to help you evaluate properties. Develop a business relationship with that agent so that you can call on him when you need to research comparable properties for an anticipated sale or purchase.