We often meet homeowners who proclaim, "I need to use every bit of available space I can for storage!"
And then they proceed to insist that these cubbies and jogs that interrupt straight walls, or sloped ceilings that angle right to the floor without any wall at all is giving them "more space." And when you try to point out how efficient closet systems work, and attempt to illustrate the point with real-time geometry, they cover their ears and drown your logic with denials. These design deniers will refuse to abandon their core belief system, that convoluted recesses and vast stretches of floor space, no matter how difficult to access is some kind of space economy. No matter how much this belief system denies logic.
The simple fact is: Wall space equals efficient closet space.
Let's take the example of a space under a stairway with a standard height 2' - 6" door as access to a 3 foot wide space that runs in 8 feet or so under the run of the stairs. About 24 square feet of floor space, right?
And to get to things you are bending or crawling in on your hands and knees, right? So if you fill the space up completely, it leaves no room to crawl in so you really get less than 24 square feet to actually use.
Now, let's freak the design denier out and suggest framing a wall to create a standard 24" deep reach-in closet. Oh my god, you are wasting so much space. Really? Well, let's install 5 adjustable 19" deep shelves for bulky storage--things like boxes or big blankets, linens, pillows, and then apply some math. Assuming the stairs are at least 3 feet wide that comes to--uh, let's see--23.75 square feet of accessible, adjustable shelving at arms reach. The same as the floor space.
But now everything is visible, reachable, and off the floor! No crawling. No jumbled piles of stuff. No hitting your head on the bottom of a stair tread trying to back out.
And yet the design denier will stand there and repeat over and over, "But I need to use everysquare inch of space I have!"
Crawl baby, crawl!