First of all a realtor will know exactly at what price to set the rent. Secondly we have the resources to list the rental everywhere including and especially on the MLS, thus expanding the potential to find a tenant through all the Realtors in the area...if the property is priced correctly a Realtor will be able to find a tenant in a week to 10 days.
In addition to what my colleagues have said below. Another consideration you might want to include is that your agent will have a good network of clients and contacts both within their own office and among their own clients. After all, real estate is relationship business â€” a referral of a trusted contact may be worth the extra premium a landlord would pay. In addition, in markets like San Francisco, there is a thicket of fair housing laws to follow. Agents should have expertise in this as well. On both counts as you can see that risk is reduced.
In addition to the fact that we know our neighborhoods, prices, and so on...it takes time. I just rented out a unit here in San Diego...I've easily spent 10 hours on this...and not everyone has the time to spare.
Also, Realtors aren't emotionally attached to the property which often makes it easier to be objective.