I started vaping with 24mg juice. The first week I was down from 2 PAD to a couple with coffee and one after each meal. Sometimes, I'd have a cig before bed. I vaped all day long with a Joye 510 cig-a-like and a fixed voltage eGo with the early A, B, and C tanks and cartridge atomizers.
I did that for a couple of years. One day I started vaping and smoking after each meal just to compare. The vape tasted good and the cig tasted pretty nasty. Once I accepted that realization I knew I could quit those last few and I did. There were no withdrawal symptoms at that point.
Earlier this year I started cutting my nic level from 24mg to 6mg. I first dropped to 18, then 12, then 6. I vaped a little harder for a few days each time, but it was really easy. I'm thinking now I could go to 0 nic and not miss it, but a little nic is supposed to be good for the mental processes. After the first week I was able to stand around smokers and vape and not want a cig. My wife smoked sitting next to me while I vaped for over a year before she used a prescription med to quit. She never really liked the tedium of vaping, even if I maintained her ecig carts for her.
Don't think that vaping is addictive like tobacco. Your cigarette is carefully designed with chemicals intended to create and maintain your addiction. Ecig juice is just plain old unadulterated nic and you can taper off without withdrawal issues. The most addictive part of vaping is that it replaces the hand to mouth actions of smoking. It gives us something to do and provides a little nic to stave off the desire for a cig.