The history of collecting and displaying plates goes back to fourteenth-century Europe, where the nobility discovered the beauty of porcelain after Chinese trade routes opened. Today, you don't have to be a monarch to have a group of beautiful collectable plates. While plates are charming display objects, some can also be valuable. Learning to asses the worth of your collectable plates is a matter of the condition of the pieces and how collectable the market deems them to be.
Consider the condition. Whether you are buying or selling, check the condition of a piece. Look for chips, cracks, or crazing, which are fine cracks in the glaze. Visible chips and cracks are the most detrimental to the plate's value. If the piece is rare, very minor damage affects the price much less.
Check price guides. A library or bookstore will have value guides for collectable plates. If you collect a specific type of plate, look for a specialised book. For example, if you are a Hummel plate collector, look for a book like "The Official Hummel Price Guide" by Heidi Von Recklinghausen. If your collection has many different kinds of plates, try a general guide such as "Decorative Plates" by Jim Harran and Susan Harran or "The Official Price Guide to Collector Plates" by Harry L. Rinker.
Assess the marketplace. Any collectable is worth only as much as a buyer is willing to pay. Talk to owners of antiques and collectibles stores to find out what is selling and for what price. Use the eBay completed auctions feature to see how much particular plates are fetching. You must set up a free account in order to use this service. The web site WorthPoint gives auction histories and prices that have been realised at online antique stores for a variety of collectibles. The Gallery Marketing Group offers a list of the high and low prices for Bradford Exchange plates and includes the original issue price for each piece.
Consult other collectors. Fellow collectable plate enthusiasts are reliable sources for information on what is hot in the marketplace and how much various plates are worth. Go to antiques and collectibles shows to converse with sellers whose booths feature collectors plates. Use a service like Meetup, which brings together people with similar interests, to see if there is a plate collectors' club near you.