Pheromones are mysterious little chemical sensors that are supposed to have a lot to do with whether or not we are attracted to people. They may also play a big part in the way people react to houses.
If you have a house on the market, it will be important to ensure that the pheromone factor is as high as possible--so that the prospects who come inside will involuntarily pull out their checkbooks and offer to pay your asking price. A good real estate agent can give you some important hints about maximizing your home's ability to attract buyers. This could mean completely airing out every room to eliminate musty odors, or allowing enough time for freshly painted walls to lose that telltale toxic smell.
Unless you are already compulsively neat, you may need to make temporary changes in your housekeeping habits to ensure that your home is both fresh-smelling and sparkling clean. Sometimes this will involve hiring a professional cleaning service. Give your real estate agent the space to speak candidly about what you need to do to make your house looks its best.