Hi
I personally don't think that you need to quit therapy if you find it has been helpful.
I have a friend who has been seeing a therapist for about 4 years now. At first, she needed to go to help her deal with issues she had but since then, she has been seeing her therapist every month. These sessions of hers are more like an update and dealing with small frustrations that occur. This has been very helpful for her so, having seen how she responds to her therapy sessions, I would recommend that others continue to work with a therapist they have built up a good relationship with...... even if it is long after their issues have been dealt with.