My husband is getting ready to lay tile in a new pantry, laundry room and hallway. All are connected and we will use the same tile for all. I know that you are supposed to start at the center point of a room to set tile, but what if you have two rooms with doors and a hallway? Should we tile in one continuous shot without thresh holds under doors? Where do we begin to figure out our starting point if we don't need thresh holds?