A 5x5 storage space is the size of a small walk-in closet. It holds one piece of furniture with a narrow footprint, tall narrow items like lamps, and 6-8 boxes.
A 10x20 storage space is the size of 2-3 Bedrooms. It holds furnishings and appliances for an average 1500 sq. ft. residence. It can also hold compact vehicles depending on width and length.