The list can be huge. Everyone has their own reasons and since its your own choice to quit, your own reasons will be more empowering than what I can bribe you with here. You can sift through extras Here and Here.
Notice: I mention finances because it is often overlooked, take a peak at how much you apply your own personal tax to an overrated activity. TALLY IT UP!
As with anything whether it is bodybuilding, strategic carpet bombing, or Burt Reynolds caricatures, you need a plan. Failing to plan is the same as planning to fail (remember this.) Smokefree.gov has great resources for this, get to planning.
COLD TURKEY! oh yes. This is the tried and true method of all smokers that have quit for 10 minutes and went right back to it. I don't believe in it. Attempt this only if you are very strong willed, or have a friend to punch you in the goods every time you slip up. (pain disassociation, I don't recommend it.)
The reality of it. If we had iron wills when it comes to this stuff, we wouldn't be reading on the internet for tips on quitting. We would instead be Googling "finger boxes" or "Cigar guy" and enjoying the best nutshots on You tube. So since we are here, lets be real.
My personal recommendations from my experience is to slowly but surely lower your intake. Next time you buy a pack take a business card and stick it in plastic wrapper around the pack. Because your the young entrepreneur that you are use the pen that you ALWAYS carry and mark on this business card every time you engage in an act of smoking. PROTIP: an act of smoking is not a cigarette. an act of smoking is everytime you put your hand to your face with a cancer stick holding the gap between your fingers and take a drag. Now imagine with me how many times you do this 10-12 per cigarette which is 200-240 times a pack. which is 1400-1680? ( i did it in my head) times a week at a pack/day. yikes , let those numbers sink in.
Counseling, Prescription medication, Preventable Death. They offer those things for suicide attempt victims as well, if these things are on the same page. C'mon open your eyes , I did and ill never go back, it's not even a thought anymore. Better breathing was my reason and it was well worth it.
Offering my congratulations now.
(if you enjoyed this please pass it on/ leave your tips in the comments below/ put someone you wish would quit in the comments.)