I don't bring backups, and haven't for years now.
I know how long my battery is going to last...
And I if my atomizer goes out on me I'll just have a few smokes if I must...
I reached the point long ago where the idea of having a smoke or two if needed does not scare me.
I'm a vaper now, and a couple of smokes here and there isn't going to change that.
But over the last few years, my atomizers have only failed a couple of times while out and about.
And usually I can just wait until I get home, and the smokes don't even come into play.
I'm not so far removed from smoking that I would trust myself if I had even just one cigarette.