Here is a list of current connections and their sync times
iCal sharing is not live availability, but here is a summary of how often iCals are polled. Just bear in mind that these are rough estimations.
Anytime Booking is every 15-30 minutes
Airbnb is every 5minutes and they only share the next 12 months of availability in their iCal feed
Booking.com is up to 30 minutes
Beds24 is every 15 minutes
Canopy & Stars is every 20 minutes
Cool Camping is every 15-30 minutes
Cottages.com is every 10 minutes
Expedia is every 30 minutes
Glampsites is every 15 minutes
Hoseasons is every 10 minutes
Mullberry Cottages is every 10 minutes
Quality Cottages is every 15 minutes
Quality Unearthed is every 15 minutes
TripAdvisor is every 30 minutes
VRBO is every 5 minutes
Yonder is every 15 minutes
Suffolk Hideaways is every 15 minutes
Bookalet is every 15 minutes
Bookster is every 5 minutes
Eviivo is every 15 minutes
Free to book is every 15 minutes
Inn Style is every 30 minutes
Lodgify is every 2 hours
Sawdays is every 15 minutes
SuperControl is every 15 minutes