Hello @aidynizquierdo, welcome to the Seller Community!
When you create a service in Square Appointments it will require a fixed amount of time for the duration of the appointment. Currently the the time duration is capped at 23 hours and 59 minutes.
In your case I would make a service called "Pet Sitting - Multiple Days". In the item description you can say something to the effect of "Please specify the day's you'll be gone in the appointment note". So when a customer books an appointment you'll be able to see what dates they're gone. This will require your clients to read and follow through on instructions.
If you have any questions please feel free to reach out to me!
