Recognizing that some clients are risk-averse in buying intangible services, I am wondering if it makes sense for me to offer some sort of "satisfaction guarantee" for my consulting services.
This is a common discussion among consultants and one that bridges two perspectives of the nature of consulting services. On the one hand, a consultant is delivering a professional service based on experience, best practices, and a commitment to the current client's interests. Consultation is not a manufactured product that can be created with a standardized process to narrow tolerances and tested for conformance. Much of the outcomes of a consultation, especially implementation of recommendations, are not under the control of the consultant. A consultant is responsible for diagnosis and recommendations; the client is responsible for accepting (or not) those recommendations and implementing them. In such cases, it is unreasonable to hold a consultant fully accountable for the impact of their services.
On the other hand, clients reasonably assume they are receiving high quality services, grounded in a consultant's professional competence and ethics. Consultants are frequently castigated for promising to provide services for which they are not qualified or making unfeasible implementation recommendations. A professional consultant, one who is committed to ethical practices and continuous improvement in consulting skills and behaviors, can promise that the diagnostic, analytic, and recommendation phases of an engagement are competently provided. These conditions are usually sufficient to assure a client that the services received for a fee, despite being customized and intangible in nature, can reasonably be expected to meet their expectations.
The point, however, is to what extent a consultant should offer to give up fees for services the client feels are unsatisfactory or offer to repeat services until a client is satisfied. Assuming a client is not trying to take advantage of a consultant, this issue comes down to what an explicit agreement between consultant and client as to what the client is buying. Clients are looking for a good outcome, of which a consultant's professional recommendations are only one part. The services are in the recommendation, not the outcome.
Tip: To avoid the unpleasant situation of a client refusing to pay for services rendered, have an explicit discussion of what you are providing. Relate this to a visit to a doctor, where your paying for the visit is not contingent on the diagnosis you receive. As long as you are providing competent and ethical services, you should not start down the path of offering to keep redoing services until a client is satisfied. There are strong opinions on both sides of this issue, but to offer refunds raises the issue in a client's mind that you are not completely confident of your professional skills and value of service.