Heat tape malfunctions pretty frequently due to improper use... If it's wired wrong or not set on a thermostat/rheostat you're virtually assured a burnout-meltdown-smoking plastic wreck within four or five years.
Now... heat tape farting out when used *properly* is an entirely different subject.
"Genes, Like Leibnitz's monads, have no windows; the higher properties of life are emergent... And once assembled, organisms have no windows." - Edward Wilson, Sociobiology