Part 2,654 in the series.
But of course, this is the time when both the water heater needs to be replaced and the boiler has some extensive plumbing work to perform.
The floods of Memorial Day weekend killed our 23 year old water heater since the completely functional sump pump was turned off and left about 8" of water in the basement. The water heater's burner is only 6" off the floor- you can do the math. For a few weeks we tried using the domestic hot water connection off the furnace but found the hot water flow too inconsistent for things like showers so a new water heater was scheduled and installed. However, while the domestic hot water was in use, we discovered that an old repair to our boiler's main heating supply line was deteriorating to the point it had to be addressed and quickly before it failed, flooding the basement yet again.
Some awesome plumbers handled the work and after a few hours of their labor over two visits we have the situation handled for the next 50 years or so.