It really depends on what type of LEGO fan you are.
Some of us build sets from the instructions, and when we aren't displaying the set it goes into a ziploc bag for storage. Whether we keep the box, flattening it to conserve space, or toss the box is another variable.
Some of us build sets from the instructions, and when we are done displaying a set we part it out for our MOC-building collection.
Some of us just buy sets for their specific parts, and immediately part them out for MOCs.
Some of us are addicted to parting out sets but never get around to building much with them.
Some of us are addicted to buying sets, never building them, and then storing the sealed boxes on every shelf and spare space we can find around the house.
Some of us (few or none in this thread) speculate in LEGO, buy large numbers of sets with high resale potential, and rent out a storage container to manage our reseller inventory.
I want to know how many of LEGO GAF fall into that category.