Water heater. To change or not to change?
 

I've got a 22 year old 40 gallon water heater that works great, no leaks. Considering the age, should I replace it before it fails at a bad time or has it got some years left in it?

Gas or electric?

For the length of time that water heater has lasted, it's served you very well. With that said, I think problems will be right around the corner. If it were me, I'd probably start shopping for a new one. I like to stay ahead of problems and prevent them before they happen but that's just me. The first problem might be a small leak or something. Not a disaster but can be an inconvenience.

Gas. Thanks for the "change it" vote. I'm leaning that way. Anyone else?

They never give when you have nothing else to do.

Ticking time bomb waiting to happen.
When you replace it add a pan under it with a drain. If it does leakit will drain off and not damage the house.

Unless it was a water heater constructed of long life materials such as the Rheem Marathon; Heat Transfer Products SuperStor Ultra, Everlast or, Phoenix; or, another brand with a Stainless Steel, Moly, Copper or, Plastic tank I would regard it as a time bomb waiting to happen.