I just received a 100w Chinese heater intended for a 90 liter (20 gallon) tank. The instructions say "Aquarium heater is consumable, we suggest to change the heater after you've used it for one year." I know there are expensive heaters that have lifetime warranties. I do not want to take the risk of the heater malfunctioning in a year's time and freezing or cooking my fish and plants. Should I return it for a more expensive one, or is this "par for the course" with all aquarium heaters and I should just buy a new one in a year even if the current one still seems fine?