The average size of most four-bedroom apartments is at least 200 square feet for one single adult living in the space. To be more comfortable, 450 or more square feet are needed for an adult size bed, bathroom, kitchen and a place to sit.
The trend has changed over time. In the 1990s, living quarters were smaller. The amount of space in an apartment rose slowly over that decade, peaked in the late 90s but then began to decrease as 2009 approached. With dynamic economic change, buyers have reconsidered the amount of space they need versus the square footage they want.