I know with heaters it's a hit or miss kind of thing with brands and all that but it's also a thing where one mistake could kill all your fish or burn your house down. So that begs the question when should you be replacing heaters? I personally have those aqueon preset heaters, some of which are pushing 5 years old now (and I forgot which ones those were in my fishroom). I have only had a heater overheat once but I caught it. That heater was also a cheap brand that only lasted about a month.