Nobody knows who first said, "To succeed, you first have to fail." But it's a phrase many smokers likely relate to. About half of all smokers try to quit each year, according to federal data. But only about 7 percent are successful.

"We've heard about people who say, 'That's it!' and they stop for good. But that's pretty rare," said tobacco researcher John Dani. "The average person makes multiple attempts before they quit."