My water heater is a power vented, 40 gal reliance heater. 15+ years old. A couple weeks ago, I had to relight the pilot light because for some reason or other it extinguished. When I was under there, I found literally, mounds of rust. Like it was shedding under there! So do I wait for a problem (could be years?) or fire a pre-emptive blow to it? It does not have an anode to change, I put it in with the "insulator" type plumbing. Never did any maintenance to it other than oil the blower once in a while.