Well I smoked for 3 years, and was smoking half a pack to a pack a day. I tried getting that vaping is a much less dangerous habit but she's really worried because no definitive testing has been done so the long term effects are unknown and it scares her. So she tells me that I can't be doing it for forever and a day.
There's been all sorts of testing. Long term, not so much as the phenomenon is too recent for data collection. But the honest testing done to date is showing there's very little harm in vaping. Sure, there are half baked, biased studies out there and if you really look at the bottom line, you'll find they really didn't find much wrong either. They just chose to portray it in the worst possible light to give ammunition to the prohibitionists who wish to ban anything and everything that looks like smoking.