Personal service workers help people who are unable to perform certain tasks because of various reasons such as being too busy or too ill. They may stand in line for license renewals, organize retirement parties, index videotape collections, or take elderly people to their doctors' appointments. There are no limits to the sizes or types of jobs personal service workers do. Personal service workers may be self-employed, or they may work for agencies that provide such services. Some workers specialize in certain services. For instance, a worker who provides stand-in services will wait in line to renew a passport or stay in a house while a new furnace is installed. Other workers who offer organizational services will alphabetize files, set up offices, or arrange garage sales. Some offer personal shopping services. These workers bring ranges of goods to choose from to the clients' homes, or they buy those items requested by the clients. Some agencies offer all of these services.