An empty unit hides nothing. Every mark you stopped seeing two years ago is suddenly the only thing in the room, and the walkthrough takes about fifteen minutes. Knowing what gets looked at, and in what order, is most of the battle.
Inspectors start in the kitchen, and they open things. Inside the oven, inside the refrigerator, inside every cabinet and drawer, under the sink, and behind the range if it pulls out. Grease on a hood filter or crumbs in a drawer runner is the most common single deduction we see, and it's entirely avoidable.
Bathrooms are next: grout lines, the base of the toilet, the underside of the seat, shower door tracks, and the exhaust fan cover. Hard water in this area leaves scale on glass and fixtures that will not wipe off with a general-purpose spray, so it needs a descaler and time, not more scrubbing.
Then the edges of every room. Baseboards, door frames, switch plates, closet shelving and rods, window tracks and sills, and light fixtures. This is where a deep clean and a quick clean visibly separate, and it's what a property manager runs a hand along while they're talking to you.
Finally, floors and walls. Vacuum carpet edges where the vacuum normally doesn't reach, mop hard floors along the baseboard line, and spot-clean scuffs where the paint finish allows it. Some walls can't be cleaned without burnishing the paint, and knowing which is which saves you from turning a small deduction into a repaint.
If you're moving out of the area and won't be there for the walkthrough, ask your cleaner for photos of the finished unit. It costs them nothing and it's the fastest way to settle a dispute you can't attend in person.