What Defines an "Antique"?
"Antique" is a loosely used word describing anything that appears to be old even if it was purchased by your grandmother in 1944. Age isn't the only defining factor when assessing any antique item. As appraisers, we examine condition, rarity, style, material, provenance, construction techniques, marks and age.
Technically the current legal definition of an antique is an item that is over 100 years old. If it was made before 1911, it is an antique; after 1912, it is "vintage". Congress declared this sliding definition in 1966. Before that, an antique was defined as predating 1830 because furniture was created by hand and not machine. After 1830 furniture became increasingly mass produced which transformed the furniture industry making goods that became available to the middle class.
Condition is the ruling factor when assessing antiques. If a furniture item is damaged or poorly restored the value plummets especially if it is commonplace. A collector will not pay a premium price on an as-is piece. Normal wear is expected. It is not mandatory for an 18th century Chippendale chair to retain its original upholstery, but original legs and feet should all be intact.
For fine glass, porcelain and pottery chips, nicks, cracks, repairs and scratches on breakable pieces will usually mean a significant loss of value. Chips on rims of glasses and china plates, spouts and porcelain figures are common which results in an almost "no-value" for a collector. Even if it has been professionally restored, it almost always significantly lowers the value. Over-all a compromised condition can devalue the marketability of an piece by as much as 75% or more.
Many mass produced items from the early 20th century through both world wars still exist in large quantities today. Though old, most of these items are not yet antique, nor are they rare. Such porcelain pieces like Haviland or Limoges tableware, dresser sets, depression glass, Nippon tea ware, reproduction colonial style furniture that many people have inherited from their grandparents are collectible in the marketplace, yet often have higher sentimental value than monetary worth. Such items are frequently found at estate sales, antique malls and on the internet. Check current and completed auction listings on eBay to help you determine how rare or common a particular piece might be on the market.
The style of an antique has a large impact on its desirability. Furniture styles and forms go in and out of fashion in cycles just like clothing. At one time, Rococo Louis XV style was in demand and fashionable, but was later replaced with the more linear neoclassical style. Furniture forms can lose their function thus rendering them obsolete. Case in point is the armoire that was once so popular for storing entertainment systems. The size and form no longer can house a 21st century plasma TV.
Of course there are other factors that relate to the value: material, provenance, and the maker that contribute to the value. The most important point is that the "antique" that you so admire has the in-place value of importance to you, your home, and family history.