The short version on Commercial Dumpster Rental: it is recurring container service for a business whose waste never really stops. If nothing else, remember this going in: collection frequency and the clearance a working lot can spare drive the cost more than the container size.
Don't assume an empty-looking container means room to spare. If what's inside is dense, the ton limit can already be spent. The booking pattern here skews toward property managers and business owners, since the job produces a fairly predictable volume of debris, which is why 20 or 30 or 40 yard containers cover most of what actually gets ordered. What decides the call quickly: the width of the path a truck needs, and whether the container sits on sidewalk that needs protecting.
A whole-house cleanout combines light junk with the occasional heavy piece, so plan around whichever runs out first, the space or the weight allowance, since either one can end the load early. Settle who is responsible for driveway damage. Concrete cracks and asphalt divots happen often enough that some haulers offer boards to spread the weight, others don't. Don't split the difference between two sizes. Pick the one that covers the heavier estimate, because running short means a second delivery, not a partial refill.