The hot water in my recently purchased home seems to be slow in
comming and does not get very hot.
The water heater is gas and is about 15 years old.
When I lit the pilot light, I saw a lot of debris on the burner.
I brushed this off but it made no difference in the problem.

Should I replace the burner or the entire heater.

I did drain the heater, first with the water main turned off and
then flushed it with the water main on. I got a lot of redish
water out of the unit.

How does one know when a water heater has reached end of life,
other than a complete failure?

B