Built a new garage. Thought about an on-demand water heater, but decided against it. In our case, it did not seem worth the risk because our area has very hard water and people seem to have problems. Ultimately the economic advantage didn't look likely, so the only advantage would be to save floor area.
So our old water heater was reinstalled in a new location "temporarily", with the plan to replace it.
The water heater appears to be 25-35 years old. But it seems to function well. No leaks, no apparent residue in the water, etc. So should I replace it? What are the factors I should consider? Are there any tests or experiments worthwhile?