If you plan to be vaping for a while, you'll end up going through a lot of these Ego-T devices.
In the days that it was all that was available it was almost one per month that would fail, if very lucky, we'd get maybe 2 months out of one.
But not just that, but also that while it can be just enough to keep someone from smoking, it's not a very "satisfying" vape compared to something just a tad larger, but light years better in terms of technology.
The Eleaf AIO and similar "All-in-one" are all great "starters" but if you're looking at long term, you should check mods that have replaceable batteries, and simple tanks with easy to get coils, for which, the Eleaf Pico kit (with the Melo3 tank) is a favourite/popular for many.
I've started to build a blog to assist newbies, so feel free to have a read (click on my name and you'll see the link to the blog), as the Melo 3 is mentioned in reference to coils..