1) Those who know what they are doing and believe they know what they are doing. They won’t use a realtor and they’ll do fine.
2) Those who know what they are doing but don’t think they know what they are doing. They will use a realtor and will be wasting the money they pay to the agent.
3) Those who don’t know what they are doing but think they do. They will not use a realtor and will get screwed.
4) Those who don’t know what they are doing and realize it. They will use a realtor and get good value for what they pay.