LONG time since I have been here. I decked in most of my back yard after
amending, tilling, replacing and spending a fortune on the lawn. No
matter what I put down or replaced it with, it turns to clay. It is
heavy clay soil that will not support grass. I left about a 10' area for
the doggies and have 5' flower beds around the perimeter of the house and
deck. Not much going on in the flower beds either.

Why do you think it "turns to clay"? What did you put down?

My soil is very much clay and a few inches of topsoil worked in has a great
lawn growing from seed in a year. For bigger plants you need to dig deeper
holes, but with decent soil around the roots the plants will adapt and break
up the clay over time.