Hypnotherapy, depending on the issue being dealt with, is often an aid to the management of the issue, particularly if you come regarding weight loss or stopping smoking. Life style may be discussed and changes suggested.
It is often difficult to gauge how many sessions will be required, because each person is unique, and sometimes what appears to be a simple problem has deeper issues behind it. But you always have a choice as to what you would like help with.
How often appointments are made is entirely flexible, depending on your time and finances. Sessions may be as frequent as once a week, or once every 4 weeks, if this is more convenient. Or you may like to have a couple of sessions, and see the response and then have further sessions 6 months later.