If your house is a typical one, there is probably some kind of small, leggy creature that makes its home with you. Whether they are termites, fleas, roaches, ants, or spiders, it is a good idea to serve them with an eviction notice before you put your home on the market. If home remedies like ionized boric acid don't work, paying a professional exterminator will be money well spent.
Most standard sales agreements require that a property be inspected before the closing and treated for termite infestation, if necessary. It is a good idea to check for insect problems as soon as you sign a listing agreement, so that they don't become an issue of contention in the sale. Some insects may not physically damage the house, but may reduce its chances of selling for top dollar. Constantly having to push back spider webs while touring the house could seriously undermine a prospective buyer's ability to fully appreciate your home.