On Friday, October 2, 2015 at 5:26:52 AM UTC-4, John Smith wrote:
Both toilets are more than 10 years old. I understand that the flapper
probably has passed its useful life. I just don't understand why it did
not leak before cleaning but did so after cleaning.


You got 10 years on a flapper? I'm lucky to get 2. I think it depends on your water.