It is great to hear that you want to quit. The first step is the 'want' to quit before you go ahead with anything else, which you seem to have achieved. But since it has been 2 yrs you have been contemplating but not moving ahead, it would be a good idea to start now. Yes, the answers you are aware of are right but you will have to understand why exactly you have to do so. Taking substances for a long time causes certain physiological changes in your body
that does not allow you to stop it suddenly. You will have many withdrawal symptoms
on sudden stoppage which is why you need detoxification
before any other treatment can be started. It means you will have to be weaned off the substances slowly and maybe with substitution therapy. The longer you wait the more damage the substances are causing your body and harder it gets to regain your health.
Coming to the issue of not having time, you have to be in best of your health to be able to continue work (that's not giving you enough time) and quitting would be an essential part of that.
Now the issue of will power, i agree it is very difficult, which is why there are structured psychological interventions like 'motivational enhancement therapy' where one is motivated from within to be able to quit. It is administered by qualified psychologists.
I hope this answered all your queries.
Dr Anjana rao