Our RV has had it's current Parallax 7345 single stage converter in it for at least 8 years of non-full-time camping use and 24/7 coach battery float use while the RV is in storage in the back yard. The original Parallax 7345 converter that came in the RV died in a couple of years of intermittent non-full-time camping use and 24/7 float use while the RV was in storage in the back yard - probably just a normal statistical early failure for it.
Our current converter seems to cool itself very effectively with variable length on/off cycles of it's quiet internal fan in all kinds of temperatures and with all kinds of electrical loads that we place on it. I see no reason for early failure of them other than the random type of early failure that we experienced. Every once in a while even the best complex equipment will suffer from statistical early failure.