When it comes to the second reason for a bathroom remodel, you and your family could be facing health risks. Bathrooms collect moisture from the sink and shower, and many older buildings were not constructed to withstand the humidity. If this is your bathroom, then that moisture may seep into the walls and wood and significantly weaken its structural integrity.
Although this may not mean that the roof is going to collapse, it does pose problems. Additionally, humidity and moisture create a ripe breeding grounds for pathogens. It is very possible that an inspection will reveal mold and mildew festering in your walls, which can be hazardous when breathed regularly.