Tom, it was explained to me that the schedule of 20 dives prior to whatever treatment, followed by 10 more provides the optimum benefit. Fewer are not enough, more will not give more benefit. Also, there is no limit on the number of times one can have a course of treatments. People who believe it provides a cosmetic benefit pay big bucks to have repeated courses of treatment. I expected to come out looking 20 years younger, but it was not to be (grin).