It happens all the time. I get a call on one of my listings from a buyer. After a few minutes of discussion, it's clear to me they did not just start looking. They have made many calls, seen many homes, met many agents, some of these callers have even written offers. Why have they not selected an agent to work with exclusively? Because they are under one of these impressions: A) that they have a better chance getting a lower price using the listing agent, B) they have a better chance of getting an offer accepted using the listing agent, and C) that the listing agent is the only one who can show that property. Buyers out there who believe these things, please allow me to share the reality of real estate buying and selling- at least in my little corner of the world.
From the three above, C is easy-- any agent can show any home. We all have the same MLS key that allows access to any home on MLS, as long as we are a member of the local MLS. If an agent isn't a member, you don't want to work with them anyway. If they can't afford to be a member of the local MLS, they are probably desperate for a paycheck and you are not a top priority-- a paycheck is.
Regarding B, you should know, on Bank Owned Homes (or REO's as they are comonly known), the listing agent is often not allowed to represent both the buyer and the seller. The listing agent will sometimes have a Buyers Agent's sign attached to their sign in front of the house. If you call this person, they will represent you and, if your offer is accepted, they will pay the listing agent a referral fee for giving them a client. Does it mean you have an advantage or you get great representation? No. These REO Buyers Agents are usually new agents with little experience who've closed very few deals and know little about the ins-and-outs of transactions. You will probably get better service and a tougher negotiator if you choose the best, most experienced agent you can and stick with them. By the way, when I say "most experienced", I don't mean they've been a Realtor for 30 years. I mean they consistently close transactions and are up to date on the market and everything that entails. On short sales, the listing agent can represent both buyer and seller but usually they won't get paid a commission for both sides. For this reason, listing agents on short sales often don't care one way or another if you use your own agent. You will certainly get better representation with your own agent as long as they are competent and ethical. Don't get me wrong, as the listing agent of a short sale you call on, I will show you all the homes that fit your criteria, not just my listing and I will happily represent you.
Regarding A, if I am the listing agent, my first duty is to the seller, after all, my agreement was with them first. If I agree to represent you as the buyer on one of my listings, I have clearly and emphatically told you that my first duty is to the seller. I promise to treat you fairly, ethically and legally as the buyer, but my fiduciary duty is first to the seller. What does this mean? Well, let me put it to you this way: if the listing wasn't mine and I didn't represent the seller too, I would negotiate for every possible thing I could to please you and still get the transaction to close. My first duty would be to you and you alone. I would not be considering how to save the seller money and get them the most money possible from the sale of their home.
The moral of this story is, don't jump from agent to agent as you house hunt. Call, email, research many agents. You will come upon one that you instantly feel a connection with. Use your intuition and gut instinct. You can reasonably expect an agent to respond within 24-48 hours to a call or email. You can reasonably expect an agent to look up tax records on a property and share what is owed on a short sale, or which bank owns the property, if it's about to go to auction, what the taxes and assessments are. You can expect your agent to find out whether there have been any offers, if it's been pending and is back on the market, if there's been a pest inspection or home inspection, as well as other information that is commonly available.
If you are skipping from listing agent to listing agent, you cannot expect any agent to make a full investment in you if you haven't invested fully in them. You simply cannot get the best service if you are not committed. My advice is pick an agent you like and stick with them. They will be looking out for your best interest because they know you are committed to the relationship.