Me: So when should we have our lines* cleaned again?
Plumber: You're going to hate me for sayin' dis, but ya know, it could be two years, it could be five years. Da best ting to do is to wait until it floods again and den ya know how long ya need to go before ya clean.
Me: I think I'll have you guys come back in three years.
* From the house to the main sewer - an attempt to keep our basement from flooding again, even though we have enjoyed these first two times so much.