By Frank Hutchison

What is the best way to write a “guarantee” on a service business?  I’m a certified health coach and educate and guide others to live their best life.  Some clients will not do what is suggested so I need solid boundaries around my guarantee.
In any service business you will always have the question of how much is the client responsible for the results?  Even if the client does everything that they are told to do, there is usually no way to guarantee that results will be what is expected.
I recently had surgery on my left shoulder and participated in physical therapy both before and after the surgery.  My doctor and my physical therapist never promised me that I would end up with full range of motion and strength (or play the violin) after the surgery and physical therapy.  What they said was that I would more likely have better range of motion and strength if I did the physical therapy faithfully than if I didn’t.  It’s choosing your words carefully to not promise what you can’t guarantee.
This is an example of a situation where an educated client is important.  As a service professional, you have a responsibility to fully explain the risks and possible benefits of your service as well as the scope of effort required to achieve results.  But that‘s the minimum you should be doing.
Personally, I have found that making it easy to tie effort with resultsor progress is important to being successful with clients.  This is really the reverse of your question because instead of focusing on protecting you from the unsatisfied client, you focus on making sure the client is satisfied with their effort.  It also gives you information needed to protect yourself from clients that expect to achieve spectacular results without any effort.  In your case, creating a self-monitoring report for your clients of the activities they are supposed to be doing vs. what they are actually doing can (1) motivate them to actually do the activities and (2) give you a record of what they are really doing.
Incidentally, I have full range of motion and getting back most of my strength in my left shoulder – because I followed instructions of my physical therapist.  But I still can’t play the violin – of course, taking lessons might help.

A physicist by trade, author by choice, a born teacher, a retired veteran, and an adamant problem solver, Frank has helped the White House, federal agencies, military offices, historical museums, manufacturers, and over 250 technology startups get stuff done, communicate effectively, and find practical solutions that work for them. In his spare time, he makes sawdust and watches Godzilla movies.