“This depends on many factors such as: severity of the disorder, student cooperation, motivation, and readiness to learn. Family involvement in implementing home practice is another significant factor. In general, children with receptive language problems (difficulty understanding language) tend to require longer courses of treatment, as do children with underlying neurocognitive impairments such as autism.”

Speech therapy is usually approved by your insurance provider for 3 to 6 months.  If your child continues to require therapy, a new authorization request for speech therapy will be made to your insurance provider.  Your child will be discharged from speech therapy once their goals are met or they have reached their maximum potential.

Source: http://www.speechpathologygroup.com/html/clinic/faqs.html#2