I have one.
I take it in for service about every five years. It usually costs a few hundred dollars.
There is not a lifetime warrenty but they will fix anything that goes wrong for a more or less resonable price.
My daughter dropped mine and broke the indestructable crystal face glass. It cost about 700 Canadian to have it fixed but that included taking apart the watch to remove every little fragment of glass, putting it all back together with new seals and pressure testing it.
Mine is now going on 17 years old. I bought it new. With the rough way I live (swimming, working on rigs for the first half of its life, diving, playing sports) I would have gone through a cheaper watch a year. So I figure I am ahead as far as cost.
Each time you take it in for a service or to get it fixed they give it back with a new 1 year warrenty.