What is a Bed and Breakfast? The term originated in the UK or the US and is now used broadly to describe any residence that provides overnight accommodations and then breakfast, obviously. More often than not, bed and breakfasts (or B and B's) are private homes that have a few extra rooms to let out to people who are just passing through, often tourists.
The owners of these establishments are expected to prepare the breakfast and to clean the rooms. But they do not prepare additional meals. A B and B is not an hotel and they do not offer room service, which means that guests must make other arrangements for dinner and lunch.
Why do people prefer bed and breakafast accommodation in Sicily? One obvious explanation is that B and B's tend to be a bit less expensive than hotels, especially in urban areas. They also offer guests more privacy. There are no chambermaids or noisy lobbies to cross. And we have yet to encounter a crowded elevator in a bed and breakfast.
But the main selling point of the B and B is that it is more comfortable, it is more like home. Tourists feel as if they are actually guests in someone's home, because they actually are. This often makes them feel less like visitors and more like friends.
Bed and breakfast owners are also generally a bit more laid back than the average hotel manager. This means that they will rarely fine you if you are fifteen minutes late for checkout or if you make one too many long distance calls.

