I started drinking often when I started 2nd year high-school, 1999/2000
I smoked my first joint when I was 4th year thru high school, 2001/02,
I started smoking cigarettes in 3rd year of university 2005/06, thats when I started smoking weed on a regular basis too.
I have nothing against any of these, nor do I think they should be banned, that only creates a big black market for them and that is far worse.
The only thing I regularly consume now is alcohol, in the form of a couple of beers a day and maybe a bottle of some spirit per week or two. I stopped smoking cigarettes, but ever so often look forward to smoking a joint with friends.
I don't know why I wrote all this, I guess to introduce u to my expertise in this field xD. Anyway my opinion is as follows:
weed is as unhealthy as tobacco, that means to be in the same risk population as tobacco smokers u would need to smoke 20 or more unshared joints a day. Pretty much no weed smoker does that. So the risk is far less.
weed has a drawback, at least for me, and that is a sort of apathy u get in to if u smoke it regularly, I lose all ambition if I smoke weed the whole day, every day for a prolonged period of time. Probably it does not affect all people like this, but this is true for most people I know. The addiction it worms is just a sort of a mental addiction, in the form: I like it why wouldn't I smoke it.
Take it in moderation, and u are safe, goes the same for anything really.
Alcohol is ok too, if u can manage to drink it in doses that make u feel better, but most of the people have no limit, and prefer to lose control, vomit and feel bad the next day.
Cigars are by far the worse, they get u addicted, smelly, u pay for them daily, they are unhealthy. They give u back nothing! that the biggest draw back for me. Nothing!
So that's all I got to say about this