Consultations in my experience evolve in two phases: PHASE 1 - Dialogue with a prospective client regarding his or her needs and providing useful information that helps the client progress and creates a good solid impression of your credibility. Phase 1 normally does not involve a contract and is marketing oriented. PHASE 2 - This phase is when the client relationship develops to the point where a discrete scope of work is surfacing involving your skill set and takes the shape of a project that will involve considerable amount of your time. At this point it is best for you to present a proposal that defines the scope of work and sets pricing, schedule and delivery terms for it. This should take the form of written contract executed by both for the protection of both.