Sometimes, you may want to increase or decrease the amount of time a customer has to book a trip before the timeslot closes. For instance, maybe your team needs a full day to prepare all the equipment for your hiking activity, and each time a new traveler books the trip, their prep work starts over. As a result, you want each timeslot for that activity to automatically close 24 hours before the event start time, regardless of any Activity Capacity Limits you may have in place.
These "book in advance" preferences are defined within your booking restriction settings — specifically, under the Auto Close Timeslots portion of the settings. For details and instructions, visit Booking Restrictions.