Trick-or-treating is a traditional Halloween custom for children and adults in some countries. In the evening before All Saints' Day (1 November), children in costumes travel from house to house, asking for treats with the phrase "Trick or treat". The "treat" is usually some form of candy, although in some cultures money is given instead. The "trick" refers to a threat, usually idle, to perform mischief on the homeowner(s) or their property if no treat is given. Trick-or-treating usually occurs on the evening of October 31. Some homeowners signal that they are willing to hand out treats by putting up Halloween decorations outside their doors; others simply leave treats available on their porches for the children to take freely. Houses may also leave their porch light on as a universal indicator that they have candy.