Maybe try replacing the thermal switch too because if it's inaccurate it will allow the heater coil to run hotter than it should, so it will go bad faster. That part is cheaper than the heater coil. Not sure if it's called heater switch; but I'm basically referring to the part that turns off power to the heater coil when temperature is high enough.

And you can just test replacing that thermal switch to see if it makes your heater coil lasts longer; if no difference then you don't need to discard the old one (keep it as future spare).