E-cigarettes have long been pitched as a healthier alternative to cigarettes, and one that could help smokers kick the habit by delivering nicotine without many of the dangerous byproducts of combustible tobacco products. [...] Now, one of the most comprehensive studies yet provides solid support for daily vaping. It found that adult cigarette smokers who also used e-cigarettes every day were 77% more likely than non-users to have quit and stayed off cigarettes after two years.