As long as they need; each person varies.
To frame this more clearly; my focus is upon the client experiencing results as soon as possible. Because I work on a deep level using powerful techniques, clients usually make rapid progress, which means that many do not need excessive periods of help.
Each case however depends on the individual and because personal development is essentially a lifelong pursuit, it boils down to whenever the client wants to stop attending. I do not run contracts because I find that clients want to keep coming back of their own accord.
A core attitude is to help clients achieve their needs as soon as possible – I do not need to ‘hang onto people’ which in any case is contrary to my essence of living.
Generally, if someone wants to learn my powerful Subconscious Mind Change techniques, that takes around 3-4 hours. Clients can then help themselves, and many do. Others return for extra assistance or to learn about/get help with other aspects.