After my lawn became a 36 hole golf course, last year, due to Minnie's excellent gardening skills, we decided on a change.
We took half the lawn away and had a large patio built, along with 4 ft fence and gates.
Now the dogs are only allowed in the lawn area when we are in it, however, one day OH didn't shut the gate properly and when I got home at night we had a six hole golf course.
Needless to say, I was not very happy as my lawn is my pride & joy, but the re-seeded areas are gradually coming back. Hopefully next year it should be fine again.
If your dogs are allowed on it all the time, you will find the urine will make a real mess and over the winter it will just get worse.