Do you need an agreement for an open house?
Why not and what is the difference between that and showing to some random potential buyer?
I had no issues scheduling showings without agreements.
YOU yourself can have your own open house there is nothing to stop you from selling your own property.
This is where it may get tricky as laws are different from State to State & Province to Province.
Yes you do need a Listing Agreement for an open house as in this agreement you state IF you want to have one or not.
Also this establishes liability. A good agent will not allow in more people than he/she can supervise.
Beware of Agent wanting long term Listing Agreements, Draw one for a short period and assess the results if you have activity even if not sold you may extend it, this way you don't fall prey of Realtors that park the listing and expect other Agents to sell, this is especially true with low commission deals.
I never did them as an agent nor do I do them as a seller. Open Houses generally is where the listing agent scouts for future prospects,
this an entirely personal decision, from a seller perspective what's the gain? You get a lot of tire kickers, once the sign goes up everyone
knows that the property is for sale, you can even specify IF you want a sign or not in the listing contract. Also as GON said what kind of agent do you want? Someone to implement your directions or someone who will guide you and counsel you on the best strategy to achieve the goal. This is where MOST sellers fall short, it's selecting the right agent, too many focus on what commission they pay rather than what services will be rendered. All I've said pertains to Ontario.

