i word for 'down the road' from my experiences:
I didn't smoke any analogs for at least a couple of weeks (was just using my various e-cigs, snus, nasal snuff, NRT devices), was still having some abrupt strong out of the blue urges for analogs (usually inspired by the power of suggestion, just seeing one, seeing one smoked, etc) but was okay until I hit a real stressful snag, had a situation that really pegged my stress and upset meter and bang, back to analogs I went for somewhere between 3 days to a week
I also happened at the end of that time to sit next to somebody who had a flaming case of some sort of catchable bronchitis
so bam, the very next day after being around the sick person ever since now I'm sick as a dog, that was my last day smoking analogs too, but my lungs are still on fire, kills me to cough, etc and I can't seem to zicam this out of me or anything, about to float in fluids trying to give my lungs a chance but they're still like a California forest fire in there
sure sitting sitting next to somebody that was contagious had to do with it -- but I haven't been sick with anything like this in literally years, even when people who were sick got near me.
So, if you can avoid it, don't go back to analogs once you do get off them, I swear it weakens and confuses your system too much and makes you more vulnerable than you would have been otherwise.
Especially during cold and flu season