You are not obliged to accept the request of a traveller. If it is not convenient for you, you just let them know. We do advise to let them know as quickly as possible to enable the traveller to find another host.
We don’t recieve many requests. In the cities, hosts may get a few requests every year, but all depends on the number of hosts in that city. When you live in the countryside, it is possible be that you will get no requests at all. When you would like to recieve more requests, see ‘members who want to receive’.