Garage Cleanout behaves differently from a standard cleanout because it is a single-room clearance complicated by everything that accumulates in a garage. Bring this up yourself if the hauler doesn't: paint, solvents, batteries and gas cylinders collect here and none of them can travel in the container.
Picture the container two ways: full to the rim, or full to the ton limit. Dense debris hits the second ceiling long before it reaches the first. The booking pattern here skews toward homeowners, since the job produces a fairly predictable volume of debris, which is why 10 or 15 yard containers cover most of what actually gets ordered. Skip the back-and-forth by knowing two things up front: clearance for delivery, and whether the container will sit on the street or the driveway.
Furniture, boxes and old fixtures take up room without weighing much, so volume decides the size here, not a hauler's weight chart. Confirm the rental period starts at delivery, not at first use, since a container that sits empty for two days still counts against the clock. Ordering slightly larger than you think you need costs less trouble than a second pickup for the overflow, so when in doubt, size up rather than risk a return trip.