One month is thought about "short-term rehab," and anything longer is considered "long-term rehabilitation." The only difference between rehab lengths is that treatment is more intensive in short-term rehabilitation because more therapy is being condensed into a much shorter time period. Unlike inpatient rehabilitation, when you choose for an outpatient program, each step of the rehab process is generally completed at a different facility.Once that's finished, the real treatment can start 90 days is typically a minimum, however lots of people continue seeing a therapist or attending group therapy for several years. The longer you invest in rehabilitation, the more expensive it will be. However, those who have extreme addictions may not receive all the assistance that they need in short-term rehab.