As with all things involved in home improvement, a simple bathroom remodeling project needs to be planned carefully before it even gets started. However, planning per se doesn't just include spending time on the drawing board for a particular bathroom design. It also involves considering and working with a number of external factors that can affect the outcome of the project itself.
Budget is probably your biggest consideration; for one, it has to factor-in the cost of materials and labor. While there are people who'd strictly follow the budget plan, it's probably best to treat it as a guide; renovation projects can go a little over-budget for many reasons. Time is another consideration because a project that takes too long to accomplish accumulates added costs. That doesn't even take into account the size and design of the bathroom itself. Inaccurate measurements and/or inappropriate design choices can push a project back by a considerable amount due to the corrections that need to be made.
Regardless of what happens during a renovation, it has to follow the local building regulations. In other words, bathroom remodeling in Chicago has to follow the Chicago Building Code, which has strict electrical and water requirements for existing and brand-new bathrooms (among other things).