The hobby of collecting includes seeking, locating, acquiring, organizing, cataloging, displaying, storing, and maintaining whatever items are of interest to the individual collector. Some collectors are generalists, accumulating merchandise, or stamps from all countries of the world. Others focus on a subtopic within their area of interest, perhaps 19th century postage stamps, milk bottle labels from Sussex, or Mongolian harnesses and tack.

The items collectors collect may be antique, or simply collectible. Antiques are collectible items at least 100 years old; collectibles are less than antique, and may even be new. Collectors and dealers may use the word vintage to describe older collectibles. Most collectibles are man-made commercial items, but some private collectors collect natural objects such as birds' eggs, butterflies, rocks, and seashells. Items which were once everyday objects may now be collectible since almost all those once produced have been destroyed or discarded (see Ephemera). Some collectors collect only in childhood while others continue to do so throughout their lives and usually modify their aims later in life. Philately, phillumeny, and deltiology (collecting postage stamps, matchboxes and postcards) are examples of forms of collecting which can be undertaken at minimal expense.