Well I smoked weed everyday for a number of months and I think I have a suggestion. Assuming the legality of the matter doesn't bother you I feel everyone should try weed once, and by try it once I mean get high off it once. The effects of it on me ranged from intense waking dreams whilst lying on my couch and listening to a band called entheogenic (I'd recommend them) to going and doing an intense work out for 3 hours. It all depends on the strain and it was wonderfully stress relieving.
That said, there are some very negative effects. Unlike most other drugs prolonged use does not make you less sensitive to the drug but more. This is because the THC will stay in your body (usually your muscles. but also your blood stream) at a concentration that is lower than what you need to get high but essentially gives you a head start. Even with that however having a supply for a month of everyday use of say middies (mid range strains don't really have a name, very common, and easy to get) can cost anywhere from 150 to 500 dollars a month depending on your area. Now while this may seem like a minor thing it is actually a huge problem, the munchies. having the munchies everyday for a month will cost about 250 dollars extra in groceries and strange food that you buy while high. It will also lead to massive weight gain. During my months of usage I gained about 25 pounds, even though I was working out everyday with a former army drill instructor and an ROTC Ranger Challenge team. So trust me, you cant just work its effects off. Prolonged usage (more than 8-9 months) can also have a permanent effect on your nervous system. While most believe that Marijuana is an upper (something that brings you up, gives you a high, or lots of energy) in reality it is a depressent like alcohol. Its effects however are very gradual and take time but are more permanent. Over time you will become more and more apathetic until it at one point can cost you your job, family, or even life. Other people live with it just fine though, a friend of mine who has been smoking for 3 years has this apathy but has a great relationship and plays in a band regularly, so the apathy need not apply to everyone. Another thing that need not apply to everyone is a leeching of energy over time the THC will drain your ability to quickly rouse energy and the dispersal of adrenaline. This effect only become a problem after years of heavy usage though.
My last tidbit however concerns quitting. Even after smoking daily for around 5 months, I was able to quit within 24 hours. While sometimes I want to smoke, it is nothing more than sometimes I want to kick the shit out of the asshole driver on the road in front of me. It is not an addictive want just a minor desire. There, that's my piece on weed. My personal motto is this though, if it doesn't grow in the ground, don't use it. (only concerning drugs)