The number of visits you will need depends on the problem you are dealing with as well as other biological, psychological and social factors. More specifically, the longer you've had the problem, the longer it will take to be resolved. Also, the existence of comorbidities, your age, anxiety disorders and the degree of your participation in the rehabilitation program are factors that affect the prognosis.
In general, the average number of visits an acute injury/disorder will require for objective improvements is 2-3 sessions. For a chronic problem (3 months+), the therapeutic approach is multifactorial and with a good participation on the part of the patient, 3-8 sessions will be needed over a period of 3 months.