The contract for services or retainer agreement serves both the Private Investigator and the client as protection in the event of a dispute. It also helps to avoid other problems such as misunderstandings, refunds, complaints, etc.

The contract agreement serves to define goals and expectations. It is rare for people to use the services of a Private Investigator more than once in their lifetime, and there are many common misconceptions of what an investigation will involve. A good investigation may achieve significant results, but they may not be the outcome for which the client had hoped. A properly executed contract helps to avoid unrealistic expectations, and clearly defines the objectives of the investigation.

Another good reason for a well-defined contract is that it establishes transparency. The payment terms and fee schedule are agreed upon, as well as the number of investigative hours to which the client has agreed.