He smoked in the 80's and then quit around 94, i think and then tooki it up again in 96. If you read teh book Starman by Micheal Francis (which is a first ahnd account) it says that Jon smoked in the 80's, and i know i read in an interview from 96 that he said he had quit and tehn in another interview from around 96 where he said that he was going to take smoknig up again after they finished touring.
But personally i think that it was stupid of him to start smoking again after he had quit, but i have never smoked so i don't know if it's hard tos top completely after you have quit, because i have friends who have quit and then taken it up again.

I agree with you that he does seem to take the easy way out during concerts, but mabye thats because he can't sing the high notes anymore, ni which case he is taking the easy way out by not having vocal lessons