Thank you for a lot of answers.
I try to make a conclusion. And that conclusion is that it takes about 3 days to get over the worst physical problems. But for some people it is "no problem" at all to quit drugs. But for for a lot of other it is a phsychological problem a looooong time after the "quitting".
And I agree that the best way to quit using drugs, is to not start using it.
If you think my conclusions are wrong, or/and you have more wiews to share, you are welcome to write them.