I think two days is a bit rich. I am sure it was more like four when I stopped.
After that, you are correct, it is merely habit. Triggers wired into your brain telling you 'now just have fag, then do that'.
If you are still craving a fag after a year then you haven't done your job in re-wiring the brain.
It took me two weeks to stop wanting one and a full year to start smoking again :(