This is a personal preference issue, but one that you want settled in advance. Many real estate agents use a "lock box," essentially a special key holder with a combination that is given to a buyer's agent. The buyer's agent brings clients to your home, opens the box, and uses the key to show people around your empty home.

It's convenient, particularly if you live a busy life and can't always be around the house to open the door for a showing. Still, many selling agents prefer to be present or to send their associates for walk-throughs, hanging around to answer questions about the home.

You can consider it either a service or a privacy issue, but consider it in advance so that you can let the agent know your preferences. Remember, you want the agent to hire you as a client; if trekking to your house for each showing is more work than she cares to do but you think their presence is important neither you nor the agent is going to be happy with the relationship.