I've been vaping for about two weeks. I, too, switch back and forth between analogs and e-cigs. At first I thought that I had "failed" every time I reached for an analog. After reading many posts here, I find that the period of transition from analogs to vaping varies with each individual. Some report switching instantly, many others report a gradual transition ranging from days to weeks to months.
The main thing is not to think of vaping as a "success" or "failure" in regard to analog use. You're basically replacing one type of learned behavior with another. The advantages of vaping - particularly getting rid of the stink and the lung congestion and irritation of analogs - will eventually lead you to prefer vaping over smoking. You won't think of it as quitting cigarettes so much as just not wanting the physical discomfort and inconvenience of them anymore.
One nice thing you can do with an e-cigarette is pull it out of your shirt pocket, take 4 or 5 drags off it, and put it back in your shirt pocket. You can't do that with a lit cigarette. E-cigs don't leave any lingering smoke or tobacco smell, so you can cop a "smoke" in an out-of-the-way spot at work and not leave any evidence behind.
BTW, I use 24 mg e-juice. At first this strength seemed too low to satisfy me need for nicotine. Now it seems fine. My issue now is trying to get over the "euphoric recall" from the old days when I could light up a cigatette, take a deep drag off it and get a momentary rush. Now when I try to relive that experience I just cough my head off.
Doc