Therapy involves a joint process between the client and the therapist. Common goals of therapy are usually to make positive changes and improve quality of life. Often, the first 2-3 sessions are for the therapist to get to know you and understand the changes you are wanting to make. During this time, the therapist will work with you to establish goals to work toward.
The number of sessions you will need to reach these goals varies from person to person. However, it is not uncommon for people to reach these goals in as little 2-3 months. There are instances where someone may need or want to continue attending sessions past the point of meeting those original goals. This is something that you and your therapist will plan together.