How can I tell if my furniture is antique?

Since most items of street furniture are of a utilitarian nature, authorities generally keep them up-to-date and replace them regularly (usually to conform to regulations, safety codes, etc.). Because of this, old, outdated, obsolete, or even non-functional street furniture can be rare sights and hold a special fascination and inspire nostalgia for many people. These "living antiques"--ancient street signs, old-fashioned mail boxes, ornate streetlamps, etc. which have never been removed and may be the only examples of their kind left in use--fascinate because they represent a tangible link to a long-gone past way of life. One can imagine, while looking at a lone 1910s-era streetlamp on a modern street, what the same street looked like in the 1910s, or the 1940s or 1970s; or imagine one of one's own grandparents leaning on the same pole as a teenager as a Ford Model T rattles by.