(CNN) -- For more than 50 years we've known that smoking can kill you.
It is still the leading cause of preventable death in the U.S. and yet 42.1 million people light up and new smokers start every day.
"Smoking is my best friend," Atlantan Barry Blackwell said. "It's always with me long after friends have left and people have gone, they are always here."
To help people who do want to quit, scientists have looked with great interest into what works. Especially since studies have shown that 90% of those who try to quit, will start smoking again despite their best efforts.
Something to keep in mind
Quitting smoking is considered one of the hardest bad health habits to break. The American Cancer Society cautions, "The truth is that quit smoking programs, like other programs that treat addictions, often have fairly low success rates. But that doesn't mean they're not worthwhile or that you should be discouraged."
If you do quit, it dramatically lowers your chances of getting lung cancer and many other types of cancer. It reduces your risk of heart disease and stroke significantly, and reduces your chances of getting other kind of lung problems. Smoking ages your skin and studies show an increasing number of people say they won't date smokers, so quitting improves your social life too.
Here are some options that have been scientifically proven to work, at least some of the time