Is there a written scope of work? A real cleaning partner hands you a room-by-room checklist, not a vague promise to 'keep it clean.' The scope is what you hold them to, and what makes competing bids comparable.
Who actually shows up, and is it the same crew each time? Consistency is the whole game in janitorial work. A rotating cast of unfamiliar faces means quality that swings week to week and a security question you don't want.
How is pricing set, and what triggers an extra charge? Good contracts price by square footage, condition, and frequency, with any extras quoted in writing before they happen. Surprise line items are a red flag.
What's the plan when something's missed? Ask how they inspect their own work and what happens when your staff finds a problem. A crew-lead inspection and a return-visit policy separate professionals from the rest.
Finally, ask about communication and specialization. You want a single point of contact, not a call center, and you want a company that understands your kind of space, whether that's a medical office, a warehouse, or a retail floor. A cleaner who does everything for everyone rarely does any of it to standard.