Is the price flat or hourly? Hourly pricing means the incentive runs against you, and it means you cannot know the cost until the job is over. A flat quote given after someone has actually seen or carefully asked about the space is the only number worth comparing.
What exactly is included? Ask for the checklist. A company that cannot tell you whether inside the oven, inside the fridge, and the baseboards are in scope will decide that question later, in its own favor, while you are at work.
Who is actually coming, and is it the same people each time? Consistency is most of what you are paying for in recurring service. A rotating cast means re-explaining your home every visit and a different standard every time.
Do they bring their own supplies and equipment? If not, you are buying products and storing a vacuum for them. If yes, ask what they use, especially if you have pets, allergies, natural stone, or unsealed wood.
What happens if something is wrong? The right answer is specific: tell us and we come back and fix it at no charge. A vague answer here predicts exactly how the conversation will go when a bathroom gets skipped.
What hours do they actually work? A company that only books nine to five cannot help a restaurant, an office, a night-shift household, or a same-day rental turnover. We run 24 hours precisely because so many of these jobs cannot happen during business hours.
None of these questions are difficult for a company that runs properly. The discomfort in the answers tells you more than the answers do.