The hobby of collecting includes seeking, locating, acquiring, organizing, cataloging, displaying, storing, and maintaining items that are of interest to an individual collector. Collections differ in a wide variety of respects, most obviously in the nature and scope of the objects contained, but also in purpose, presentation, and so forth. The range of possible subjects for a collection is practically unlimited, and collectors have realised a vast number of these possibilities in practice, although some are much more popular than others. In collections of manufactured items, the objects may be antique or simply collectable. Antiques are collectable items at least 100 years old, while other collectables are arbitrarily recent. The word vintage describes relatively old collectables that are not yet antiques. Collecting is a childhood hobby for some people, but for others a lifelong pursuit or something started in adulthood. Collectors who begin early in life often modify their aims when they get older. Some novice collectors start purchasing items that appeal to them then slowly work at learning how to build a collection, while others prefer to develop some background in the field before starting to buy items. The emergence of the internet as a global forum for different collectors has resulted in many isolated enthusiasts finding each other. Types of collection The most obvious way to categorize collections is by the type of objects collected. Most collections are of manufactured commercial items, but natural objects such as birds' eggs, butterflies, rocks, and seashells can also be the subject of a collection. For some collectors, the criterion for inclusion might not be the type of object but some incidental property such as the identity of its original owner. Some collectors are generalists with very broad criteria for inclusion, while others focus on a subtopic within their area of interest. Some collectors accumulate arbitrarily many objects that meet the thematic and quality requirements of their collection, others—called completists or completionists—aim to acquire all items in a well-defined set that can in principle be completed, and others seek a limited number of items per category (e.g. one representative item per year of manufacture or place of purchase). Collecting items by country (e.g. one collectible per country) is very common. The monetary value of objects is important to some collectors but irrelevant to others. Some collectors maintain objects in pristine condition, while others use the items they collect. Value of collected items