I (idiotically) started heavily smoking my jr year (despite running in track) and started vaping mid-May of last year to quit. It's actually helped me a lot and I now only use no-nicotine juices. For flavor now cause it tastes pretty good. I have two different ones. Ones a pretty big box I use when I know I'll be gone for periods of time, usually when I'm driving somewhere more than an hour away, and it lasts about two days straight of regular usage without charging. I love that one! The others my small "quickie" e-cig. Last about a couple hours of constant usage and can't hold half as much juice. But that one is used when I know I'll be gone for a couple hours and it will last me.
In fact, using these now has significantly decreased my need to smoke at all. Even those get used little. Only when I'm driving all over the place is when you'll see me using them often. Plus it leaves no real smoke smell at all, so if I'm driving in my granmas car and happen to use it, she won't know because it just leaves behind a slight fruity scent and even that goes away after a while.
The only downside is the 'we get it, you vape' jokes. Like all the time. So if you're going to start, be prepared.