A guesthouse owner who had read that scent improves reviews and arrived planning to put a diffuser in all nine rooms.
We talked him out of most of it. A guest who dislikes a scent in a public area walks through it in ten seconds. A guest who dislikes it in their own room, on an island, with the windows shut because of the air conditioning, is stuck with it for four nights.
What went in was one reed diffuser in reception, one in the corridor, a neutral room spray used by housekeeping at changeover only, and nothing else. The monthly refill cost is about a quarter of what nine rooms would have been.
Eighteen months on they have added one more diffuser, in the dining area, and taken the corridor one out because the corridor is open to the sea air and the scent was simply leaving.