I have had several clients come to see me this year for help to stop biting their nails. Nail biting is usually an automatic habit, the "biter" is usually completely unaware that they are doing it until someone shouts "stop biting your nails."
Most automatic habits can be overcome with one session of direct suggestion hypnosis usually involving some sort of visualisation techniques to help the client see themselves with perfect, healthy nails. In my experience, and remember that hypnotherapists are as different as chalk and cheese, as night and day, one session is usually enough in around 90% of cases to ensure that the habit is stopped.
What happens if the habit continues?
We then go into the realms of finding the cause and fixing it. Hypnoanalysis is used to uncover or discover the "reason" that the subconscious mind has to continue the habit. Once this "reason" is known, the subconscious mind can accept that the unwanted behaviour is no longer required and a permanent and beneficial change could be made. Usually this only requires one session of hypnoanalysis or regression work.
So, if you want to stop biting your nails, this could be achieved in one or two sessions.
Be happy,
Dave.