Since 2009 maybe. Been on 95mg/day for probably over 6 years until going down to 75 mg/day within the last 2 months. 
Side note: this is my second time on methadone "maintenance therapy", having successfully detoxed once before from 140mg/day. (Quick withdrawal due to legal reasons). That was in 2006. I detoxed then went into impatient treatment where I spent 30 days and then transitioned to a halfway house where I spent another 2 1/2 months. From there I went to jail for 4 months. I can say detoxing was HELL, but I had a second chance at life while staying completely clean for TWO YEARS post jail! Unfortunately I eventually got back into opiates, my addiction grew through a couple-few years until I made the GOD AWEFUL decision to return to Methadone. It's now been way too long and I've always intended to detox and get away from this nightmare once and for all. I have great support and have since eliminated any drug friends I knew. I have been struggling HARD trying to figure out how to get off this "program" for Far too long. It Is RUINING MY LIFE AND I HARE MYSELF. Methadone has caused so many issues with me (health/relationship-wise) and I hate myself for the decisions I've made Every day. Most of my family, including one adult child amd two children, do not know about my "drug habits" at this point so it is impossible to find a way to kick it. Although supportive, My wife has threatened to remove her and the children from me when I suffer the terrible symptoms of detoxing. It is not quick in the traditional ways, so I have prayed time amd time again that I can find a way to rid my receptors of the opiates and get another chance at life. I plan on possibly getting on Naltrexone or something after I kick the methadone, in order to have a second fall back option in the event I have the idea to take opiates ever again. Otherwise I have no idea where to even get any anymore amd if I ever were to kick this for good, I don't think I would EVER give up life like this again! 

I NEED A WAY TO BREAK FREE FROM THIS DRUG :( I'm crying while writing this because I just care so much for my family but constantly am bashing myself in extreme Guilt and SHAME 