Based on my own experience after injecting almost a bundle a day for a year my withdrawals will last about 5 to 8 days for physical to go away but after the first 4 days it isn't as rough..i would say it takes anywhere from a month to a couple of months for the mental craving to fully go away but that all depends on what your doing with your free time..are you keeping yourself busy with positive reinforcements and things like that..But i will say this - after your clean your life will change dramatically in the way of just feeling better about yourself to accomplishing more with your life..good luck stay clean