Good question. Why should you use an estate agent when that guy in the bar has assured you he can find you exactly what you are looking for – as a favour, naturally!
Firstly, an established estate agent with a well-appointed office has his/her reputation to protect. Bad news travels fast, and any mal practice or inefficiency would soon be common knowledge.
More importantly, a good estate agent will have knowledge of how the real estate law works in Spain. This is different from real estate law in some other countries, and most definitely different from the law in the United Kingdom, from which country the majority of home buyers originate. Of course, sensible property buyers will employ the services of a lawyer qualified in Spanish law, but it is usually the real estate agent who draws up the initial contract between the two parties, which stipulates the non-returnable deposit. The wording of this contract is very important. I know of a recent case where the seller tried to backtrack on the agreement, and get out of the contract, as he had received a higher offer, but because the experienced estate agent had worded it very precisely, the seller was obliged to proceed with the sale.
Again, a qualified estate agent will be affiliated to the association of estate agents, and he will have had to pass real estate examinations.
Frequently a buyer doesn’t really know what he is looking for, or what types of properties are on offer in this part of the world, and a good estate agent will help the client to eliminate, or indeed add to, the various possibilities.
More obviously, an estate agent will have a good portfolio of properties, covering re-sales as well as new apartments, villas, town houses, country properties, plots of land, and commercial properties. He/she can show clients far more than they could find on their own.
Estate agents do not just sell a property and say good-bye. After sales help is important, and a good agent will offer to arrange the electricity, telephone, and anything else involved in setting up a home in a new country.
Many agencies have a rental department, and are happy to take on their books the property they have just sold. So please, act as you would in your home country. Walk away from that guy in the bar, and consult the professionals!