As I understand it, a major failure is preceded by a couple days of dripping. So you could buy a $10 water alarm and place it on the floor.

On the other hand (as I understand it), having a water heater full of mineral calcification is not an efficient use of heating fuels. And you have the advantage of shopping without urgent duress.

We had a Rheem from 1986 that finally failed last year. I was a hold-out. Thinking about it later, I probably should have just replaced it sooner for the efficiency and peace of mind.

We did the same and replaced it only when it leaked. Problem is then you have to turn of the water supply and and not use the heater until you can emergently get a plumber out. You are limited to the water heater that they can get quickly. and have to take time off work unexpectedly.

So in retrospect i would have done my research and scheduled everything so that I could have control of my time and materials. By the way, you will probably be required to bring the new water heater up to code- ?expansion tank?- and that cost an extra $130 I think .
HTH

A neighbor with an old water heater got up one morning and there was no hot water. That is, there was no water coming out of the tap when only the hot water faucet was on. (Water available when the cold water faucet was turned on.) Upon going to the basement, they discovered the bottom of the tank had rusted out and collapsed dumping the entire tank contents and the continued running of the cold supply on to the floor. They claimed there was no leaking before. I find it hard to believe they didn't hear anything, but that's what they said.

I'd change it now for the convenience as scrappy said. Do your research to find the model you like. At your convenience, DIY install or have it installed.

You answered your own question in asking if it's a ticking time bomb. I believe the answer is Yes and it's been ticking for many years already.

If you have no natural gas service and are stuck with having an electric unit, I think frequent contributor Saltidawg would suggest you consider a hybrid heat pump electric water heater. Ask your plumber if something like that is feasible in your area and at the location where your current unit is located.

Thanks for the advice. Shopping around for what I want without being under duress of an emergency is definitely a good point. I will be replacing it with another Rheem, considering how long this one has lasted. Unfortunately, the heat pump option won't be possible because the current water heater sits underneath an air handler that is mounted directly overhead. The heat pump models are a lot taller than a standard heater.