Addiction Research Expert William White examines the data known today and suggests that after 5 years of recovery, things seem to stabilize for most people, requiring a greater force at that time to toss them into relapse.
See from his blog below:
For years I have been asked when recovery from alcohol or drug dependence reaches a point of durability, or put another way, “When does recovery today predict recovery for life?” After investigating all of the scientific evidence I could locate on this question, I have regularly responded that this point of durability seems to be reached at 4-5 years of continuous recovery, meaning that less than 15% of those who reach that point will re-experience active addiction within their lifetime (with opioid addiction potentially being closer to the 25% mark). This means that if you reach the 5-year recovery benchmark, your risk of again meeting diagnostic criteria for a substance use disorder is similar to the risk for such a diagnosis within the general population. (Ironically, this 5-year benchmark is strikingly similar to the durability point for cancer remission.) Reaching this benchmark is not the assurance of invulnerability, but it does mark a point at which a much greater force is needed to destabilize recovery. I have used this finding to argue that all persons treated for addiction should be afforded five years of post-treatment recovery checkups (e.g., monitoring and support) on par with that afforded most cancer patients in the U.S.