this thread is very interesting.
my 2c. when i was pregnant i consulted a number of books and found different advice in them regarding alcohol, caffeine, diet etc.
the most extreme differences of opinion were over alcohol. the things i read ran the gamut from, "give up alcohol three months before you start to try to conceive" to, "it's ok to have one unit per day all the way through" ("emma's diary" - in case anyone can't believe that - this is Oct 2001 btw!) i remember the earnest advice in one book (i think it was "what to expect..." that if you drank 9+ units of alcohol per day your baby was almost certain to have foetal alcohol syndrome - the reason i mention this being it would seem that if you drank 9+ units per day you would have TONS of problems in any event!
some books said absolutely no caffeine, others said a limited amount was ok - this was backed up by midwives advice.
the only thing that was absolutely consistent from all sources of advice was to give up smoking immediately.
i did give up smoking when i got my positive test. i had a similar lifestyle to the one janus describes, which i had to give up overnight. janus, i still miss the lifestyle! how about you?
BUT giving up smoking was absolutely the hardest thing, giving up alcohol was NOTHING by comparison, a minor inconvenience.
i also learned from the midwives (can't remember how it came up) that it is actually a tiny proportion of women who quit smoking when pregnant.
i suppose my point with this is that a bit more support and a little less sitting in judgement might be more likely to achieve the desired result.