A full bathroom offers everything you could need — e.g., a sink, toilet, shower, and maybe even a tub. Full bathrooms also add value to a home when it comes time to list the property for rent or sale.
No matter how clever you are, not all spaces can be converted into full bathrooms. Generally, at least 30 square feet is required to accommodate a small shower stall. For a tub, your bathroom will need to be at least 40 square feet.