If you manage a time-based business and take bookings for your services then you need to select the basic time-period for which you are available. To set this go to Site Admin - Settings - Service Settings and choose from the options under Service Type:
Day-based You take bookings for single or multiple days.
Week-based For services such as property rental, you may take week-based bookings
Fixed Time Services that are booked in set time slots (eg 1 hour), such as tennis courts, piano lessons or physiotherapy
Variable Flex Time Sometimes the same service can last a different length of time that changes due to options, requirements, or to allow for travel time between appointments
A mix of time ranges If you are a complex business with a mix of services choose this for full versatility. Important - Turning this setting on will add a great number of different options to you business and should not be switched on lightly