Are your cleaners screened and insured? This is the first question because it is the one with real consequences. A company that hesitates, or that answers about the owner rather than the people who will actually be in your home, has told you what you needed to know.
Is the price flat or hourly? An hourly rate means the incentive runs against you, and it means you cannot budget. A flat written quote based on a walkthrough means the company has to be accurate and efficient, and you know the number before anything starts.
Do I get the same crew? Consistency is most of what makes a recurring service worth paying for. Learning a home takes a visit or two, and if the faces change every time, you spend the first ten minutes of every visit explaining the same things again.
What is actually on the checklist? Ask for it in writing. Vague answers about a thorough clean are how baseboards, cabinet tops, and window tracks quietly stop being included. A written checklist makes the scope inspectable in both directions.
What happens if something is missed? The right answer is that they come back and redo it at no charge, within a stated window. Ours is 24 hours. A company without a stated policy is telling you that fixing it will be a negotiation.
And finally: how do you handle my building? In Jersey City, Hoboken, Fort Lee, and across Manhattan, service elevators, front-desk check-in, and certificates of insurance for management are part of the job. A company that has not dealt with any of that will find out on your time.