Question: I suspect my husband of being unfaithful. My lawyer suggests that I hire a private detective to "get the goods" on him and his girlfriend. He referred me to a detective who insists that I pay a $7,000 non-refundable retainer and also pay each agent who works on the case an hourly rate plus expenses. Does the detective have to catch them in the act to get my proof? If not, what proof is necessary? How do I know I can trust the detectives? And, how can I control my expenses?

Answer: It is not necessary to find two people in the act of intimacy to prove adultery. Proof can consist of showing the opportunity to be intimate. For example, two people enter a motel room or an apartment and remain there for several hours, and there is inclination to be intimate. Or, there is evidence of the couple walking hand in hand, kissing, or sending each other letters or e-mails. In addition, with such public Internet sites as match.com and Facebook.com, periodic checks may lead to competent evidence. In addition, when legal, detectives also use global positioning system devices to track comings and goings. Evidence can be direct or circumstantial, but it must be clear and convincing. Your lawyer can explain the applicable rules in your state.

Experienced matrimonial lawyers refer clients only to experienced, licensed investigators who know how to find out early whether there's smoke where you think there's fire. Good investigators substantiate their claims with photographs or video footage that corroborates what the detective says happened.

Before you hire a detective, it’s always a good idea to find out how the agency recruits and trains agents. Ask about the owner about agent turnover rate. Learn which agents will be working on your case and their backgrounds. Ask whether the agents who work on your case will be in telephonic contact. In order to assure continuity in your investigation, only agents familiar with your case should be allowed to work on it.

How do you control your expenses? Don't sign an agreement until you are informed in advance of what is going to be done and when. Be available to discuss ongoing surveillance with your lawyer and to make decisions on a day-to-day basis – and be on call at night when the investigators may need to talk to you.

As to the non-refundable retainers, this is a contract issue between you and the investigator. It would appear that if you pay $7,000 and the cost of securing the proof is $5,500, you should get a refund. What you pay should be applied against the per-agent rates and the agreed expenses. And make sure that if more than one or two agents work the case, there is a very good reason – such as the need to follow two cars out of town.

Lastly, be your own "risk manager." Make sure the investigator indemnifies you from potential claims by your spouse and third persons that while working for you, the detective trespassed, invaded someone's privacy, or used illegal means to try to get evidence. And find out if the detective has errors-and-omissions insurance coverage.

Question: I am divorced and looking to complete my new will and various powers of attorney. Since I no longer have a husband, I’m concerned about whom to appoint as my health care agent. What is the common practice here?

Answer: One of your most important decisions before signing a health care power of attorney is choosing the person you want to act as your agent and discussing your intentions with him or her. Your health care agent need not be your spouse. It can be parent or a child over age 18 whom you trust. After you sign the document, you should give your agent a list of your health care desires, including your feelings about life support and extraordinary life-prolonging medical procedures. Then if your agent is later called on to make decisions, he or she will be able to act effectively on your behalf and, it is hoped, eliminate family disputes that can occur during these trying times.

Unlike your will, your health care documents should not be placed in a safety deposit box. We suggest that you give your agent, your doctor, and close friends copies of these documents because they will do you no good if the people who will be around you in the hospital don't know they exist. We also suggest that you talk with your doctor to make sure he or she understands your desires, and use the opportunity to introduce your agent to this important health care provider.