Plenty of people will be kickstarting 2020 with a pledge to quit smoking cigarettes and turn to vaping, instead.
E-cigarettes allow you to inhale nicotine in a vapour rather than smoke, and are the most popular alternative to cigarettes.
Many people are concerned about how safe they are to use, though.
The NHS insists that vaping is significantly less harmful than smoking nicotine because they don't burn tobacco and don't produce tar or carbon monoxide - two of the most damaging elements in tobacco smoke.
According to the NHS, thousands of people in the UK have successfully quit smoking with the help of an e-cigarette and there's growing evidence of their effectiveness.
On it's website, it cites a major UK clinical trial that found people who used e-cigarettes to quit smoking - combined with face-to-face support - were twice as likely to succeed as people who used other nicotine replacement products.
In 2019 researchers from Queen's University in Belfast revealed that using e-cigarettes may carry the same risks as smoking tobacco.
Experts found there is "little difference" in the effect of tobacco smoke and vapour on bacteria often found in the lungs.
They found an increase in the potential of bacteria to cause harm when exposed to both cigarette smoke extract and e-cigarette vapour.
A European health body also refused to back vaping as a safe aid to quitting smoking and said there is no evidence that the alternative method is safe.
The European Respiratory Society (ERS) said that these "harm reduction" methods of quitting smoking should only be used for high-risk smokers rather than the general population.