What digs deeply into profits (or your personal financial situation) is having a 5 bedroom house with a basement when you don't need the space. You're paying for a "storage unit" with every extra bedroom, at a premium cost (or, if the house is paid off, you're losing out on investing elsewhere, at a higher rate of return, the money you spent on the too-big house). Move to a smaller place and you'll make up the difference for several storage units in property taxes, utilities, upkeep...
Storage units are cheaper, and simply a cost of doing business, like bubblewrap and coffee filters.
I don't know if I'd classify our disposable income as "large" (to some it would be, to others not), but I tell every penny of it where to go and what to do when it gets there (yes, I'm just as bossy with my money as I am with everything else ) and our storage unit is a pretty small blip on our business expense radar each month.