I live in 144 unit condo complex. All the water heaters are around 11 years old. Many have been replaced in the past year. I havent replaced mine for two reasons,1. Mine is working fine 2. I have my condo up for sale and I could really do without the expense. I have neighbors of mine warning me to be considerate of the neighbor who lives below me, and that there could be water damage to their unit if I wait. What would cause the tank to leak just because it is older in age? Should I replace my tank and not take a chance on water damage or is the odds of something happening so low that I can wait? I would appreciate some info on this. Thanks