When do you change water heater?

[Al Pat]

I have been contemplating this myself for a while. Every time when I have a midnight emergency, its about leaky water heater that is about 6+ years old. Do you wait to replace water heater till it fail or you have a system of replacing it when it is about 6-7 years old to avert an emergency and treat it more like a planned maintenance? On the other hand, some of my units are still going strong after 11 years with the old water heaters. The ones that are failing were put in service by me about 5-6 years ago. Some must have changed in how they make them these days, but I don't like getting these calls, I rather do it on my own schedule before it fails. How do you all with multiple properties deal with this for peace of mind? I have multiple properties so, will have to plan carefully.