The pump has a klixon thermal fuse that is supposed to shut down when it overheats, and to my knowledge it has never triggered. The fuse isn't the thing that's failing because the first thing I always try is bypassing the klixon.
I doubt my environment temperature is a major issue, as I live in New Hampshire and my house is quite cool for much of the year. And yes I have had failures in the winter.
The Anita doesn't have any ventilation slats on the bottom, just at the top in the cup warmer area. My machine sits on a kitchen counter, with space to either side, so it has room to breathe. There is a cabinet overhanging it which I'm sure doesn't help, but that's not exactly an uncommon configuration. Since the water reservoir is sitting inside the hot housing heating up that doesn't help the pumps thermal situation, but of course every non-plumbed machine has the same issue. The pump is actually rated for water input temperatures no greater than 25C, and obviously any espresso machine with an internal reservoir is going to have higher temperatures than that. Still, many others are in the same boat, as virtually every vibe pump machine uses this same pump.
Issues with these pumps are not uncommon, but I do seem to have particularly bad luck with it. I don't guess I can rule out that something unique about my configuration is exaggerating the problem, but I don't know what it would be.
As to mounting a pump externally, that might well work, but I'd rather not go there, and frankly I shouldn't have to. I use the machine as designed, and it should work. Can't afford it at the moment, but I've got an itch for a double boiler machine, and I'll buy one of those (with a rotary pump, for sure) before I do any extensive modding of this machine.
On the upside, i've gotten pretty good at changing out pumps.