In line with sticking to the existing footprint is the goal of leaving plumbing and fixtures in place. Yes, it might be ideal if you could move the toilet and sink, or switch the placement of the shower, but if it means tearing up floors and walls to install new plumbing, the budget will skyrocket.
As writer Cheryl Freeman discovered, “Changing the layout of the room entirely, or even marginally, to accommodate plumbing in different areas of the room could significantly raise the cost of a renovation, especially when considering installation costs. So it’s recommended you try to use existing plumbing and not drastically change the layout of your room.”