Here is Rover's definition of the amount of time covered by house sitting:
https://support.rover.com/hc/en-us/ar...
However, every sitter sets his/her own rules and they vary widely from what I've read here. At times, the client may determine that staying at the house overnight may not be needed. In other cases, the sitter may only offer a service in which they stay at the house from 7 pm to 7 am and then charge the customer for additional services like walks or drop-ins during the day.
Everyone seems to have their own definition. I happen to believe that most sitters here on Rover underprice this service. It should be considered a premium service because you are not only watching their furbaby but also doing little household tasks like taking in the mail, watering plants, etc., while the owner is gone. Moreover, staying the night gives some people more assurance that their home is safeguarded during their absence. So charging a measley $25 a night is ridiculous. I see your rate is more realistic. Congrats.
Remember, even though you may commit to 24 hours of pet care for each billable "night" of the stay, you are not tied to the home. You can come and go, walk other dogs, whatever. When I board dogs, especially repeat customers, I can leave them alone for 3-4 hours max. So long as you communicate this to the customer and they know how long you'll be gone, then you should be good.