You have 48 hours to formally respond to a booking request, although it’s highly recommended that you answer within 24 hours. If you leave a request unattended and it expires, this will have an impact on the positioning of your experience in the search results.
Remember that you are not obliged to accept any requests. If you don’t find it adequate or if it doesn’t fit your schedule for that day: simply decline it. If you decline one booking request it doesn’t negatively affect your position in search results.