Of course your provider should keep your coop to your cleanliness standards. But we don't just mean how clean they make your coop, we mean how clean they keep their equipment and shoes. Each flock has been exposed to different germs and you don't want to bring those germs into contact with your flock. If a service provider doesn't take cleanliness seriously, they'll bring those germs with them from on flock to another. Ask any provider what their cleaning processes between each appointment are before you start working with them.
If your coop care provider doesn't care about your chickens, you can bet they won't provide them with a top notch environment. Pay attention to how they act around your flock to ensure that your flock is as comfortable with them as you are!
Ask providers how they adapt to different flocks and types of coops and beware a one size fits all approach. Every coop is as different as the personalities of your individual chooks. Everything from cleaning supplies used to the time of day and visit cadence depends on a multitude of factors that will change with every flock!