When I tell people I built a new oven, they often ask "Where?"
"Same spot as the old oven."
"What did you do with the old one?
"I destroyed it."
Their reaction is priceless.
The truth is, I loved demolishing my best clay oven, and loved demolishing the clay oven before that one. When the process of building is as pleasant as getting muddy with friends, I don't mind tearing the product down.
Besides, you learn something from taking an oven apart.
Notice how the inner two inches of clay has vitrified and turned an orange-red? Notice how the insulating sawdust/clay layer the sawdust has burned out? Notice how the fired brick are blackened on the bottom, the side that was embedded in clay, not the side that was exposed to the heat? Why is that?
And, of course, much of the material from a clay oven can be recycled into another oven. The bottles from my first oven were used in my second oven. There's a few fire-brick that have enjoyed three different oven hearths, including the masonry oven I bake in today. I even used the vitrified clay from the dome as filler in the stone walls next to my new oven.
The upshot? When I hear people stressing about where or when or how big their clay oven should be, I say this: "Don't worry about. Just build something. If you have to destroy it in a year, then destroy it."
I bet you'll love demolishing your best clay oven.