Most North Shore garages fail for the same reason: they absorbed every unfinished project. The first useful step is a keep-pile. Mark what stays. Everything else can be evaluated as donate, recycle, or remove.
Sports gear, paint, and leftover lumber are the items that stall a cleanout. Tell the crew what is hazardous. Leave a path to the door. If the garage is also a workshop, decide whether the workbench stays before anyone arrives.
A finished garage cleanout should give you parking or a clear work floor. If the space still cannot be used, the job was only a partial haul. Ask for a swept floor and a short walk-through before the crew leaves.