Buying a house that is not listed on the open market has potential advantages and disadvantages.
Determining why the owner is choosing to sell the home themselves will give you a good idea as to what kind of a transaction you will have.
Owners selling their own homes tend to be more emotional during a transaction. This can lead to a rollercoaster experience from the buyer's perspective. Negotiations after an inspection report can be tricky to navigate. It is difficult to separate sentimental value from fair market value. This is one of the benefits to using a realtor.
Using a realtor can give you a real advantage if you buy a home that is sold by an owner not on the open market.