When you consider the fact that it costs you nothing to have a Realtor represent you in your purchase, you can wonder why anyone would consider not using one. Compensation paid to the buyers' agent comes from the commission that is paid to the listing agent by the seller, the buyer pays no commission to any agent. Even if you've bought several properties already and are familiar with the process, it still doesn't make sense not to have professional representation, especially if it costs you nothing.
The job of your Realtor when representing you is to facilitate the entire process, from helping you to obtain financing to the close of escrow and everything in between. Some of the primary duties your Realtor will have include: searching for, identifying and showing you properties, investigating disclosures on properties you are interested in, preparing purchase contracts, negotiating on your behalf, coordinating inspections and appraisals, and overseeing the escrow process until the close. My duty to my clients is to put their interests above all others, even my own. This is known as a "fiduciary" responsibility.