A question always asked these days by new clients. The answer, no one is the same , no issues are the same, similar maybe , but clients with similar issues react in different ways.
I have had clients that have had one session and their issue has been completely resolved.
It is quite ironic that with a lot of other types of treatment and therapies these days, people readily accept things could take some time, yet with Hypnotherapy, even though some folk are still "Its all a bit hocus pocus" they still expect it to work almost instantly.
So, what would I recommend, well, I always say it's beneficial to have a minimum of two sessions. The reason for this, is sometimes on the first visit the client rapport and trust is beginning , but not complete, meaning there maybe issues that me as your Therapist are not yet privy to, which could in turn hold the session back. People naturally don't trust anyone completely professional or not, on first meeting, and I would not fall out with this, I'm completely ok with the fact I have to earn and gain trust and respect from the way I communicate and care for my clients.
There are a number of studies which show that long term change is linked to regular reinforcement, and the more the reinforcement the greater the change and more sustainable it becomes. But in our situation we have to be mindful of the financial cost to such a commitment, and to make sure the right person is benefitting appropriately, that being the client.
I always promise that as soon as I, in my opinion a client is not benefiting from more sessions, I will stop, in fact I rarely look past two or three sessions, with maybe a follow up in a few months time if needed.
Below is a link to an article from The Guardian regarding therapy and its effectiveness, that may be of interest.