Just one. I ve given a little stuff out to learn it wasnt "their thing" so I'm not doing that. I never bother trying anymore. A person really has to want something and they'll figure it out. Vaping is pretty much common knowledge now. If they want to quit bad enough they'll do it.
My 29 I year old daughter was the one. She had quit for years but got back on. Not happy but looking for appetite control i suspect. She came up last month to visit and saw my with Teenas drip tip, tried it ( saw her suppress that cough that threatens and try some more...heh heh. Love that girl) I sent her eRoll kit, a joyetec atty and mini VV, charger WTA and regular DIY stuff and she's vaping now. Helps she has friends who vape....like one is her boyfriend. It was all used stuff because I figured she'd not go for it. Too complicated. She's works a lot of hours but I was wrong. Good. She's got asthma! No way should people with asthma ever smoke! Such a super wrong move