I think you also have been at it for some time. for me it's barely been a year and a half, and I spent much of the beginning at high nic levels. Hopefully I'll get to the point of not getting bent out of shape if I don't have my vape for some time, but even if I do, I'll still vape. I just plain like it.
I think time is less the case than nicotine levels, to be honest. I felt like I could quit vaping by the time I had been vaping for a year ... I tried and was unsuccessful at that time, but it doesn't change the fact that by then I was able to leave the house, accidentally forgetting my vape, for hours and never even miss the fact I had forgotten it. And by then I was forgetting it all the time, it just wasn't foremost in my mind by then.
As to why that was, we can sit around and analyse, (lol.. heck I do!) But that was where I was by the 1 year mark.
Now.. my vaping habits were probably always drastically different than yours.. first, I went from smoking two packs a day (i was a full flavor smoker) to using a 1000 mah ego and a ce4 that I bought for 10 bucks. I used this for the first year, and no I wasn't dual using.
I went through withdrawals even with vaping that were fairly severe in the beginning of the switch but I stuck with vaping anyway. I was only vaping 18mg/ml e juice.. and only consuming around 2 ml a day. A 10 ml bottle of juice was lasting me 8 days on average, even WITH constant chain vaping.. lol..
I think by the time my body fully adjusted to not smoking, I was nearly over the whole nicotine thing at the same time, as my amounts were negligible in all honesty.
So.. this is probably much of the difference.. I went from chain vaping my rear off, to using it more like a cigarette, to forgetting it half the time..
That progression for me was fairly quick, but perhaps in large part it was due to how and what I was vaping..
And even now, with my consumption higher (I use around 5ml a day) my nic level is still low.. I use 3 mg/ml of nic now, and that because I think nic makes my juice taste better.