If a collector is simply looking for pieces for display purposes, a chip or hairline crack may not detract from the beauty of the piece. But these pieces do have less value than a piece in perfect condition.
Study the Piece Before Purchasing.
Antique ceramics are more apt to show some wear, aside from obvious chips and cracks. If the piece is held up to the light, scratches from utensils may appear to be much stronger and the amount of use and wear plays a role in valuing the piece.Run a finger around the base of the piece to feel for smaller chips. Run fingers all over the piece to feel for hair line cracks, flaws the eyes may not see.
Carry a jeweler's loupe or magnifying glass when out foraging for pieces to add to a collection. There is nothing more disappointing that getting a lovely Shelly tea pot home and finding a hairline crack or a repair to the handle.
Gently ping the piece with a finger and listen how it sounds. If it's a flat sound like a thud, it likely has an invisible hairline crack. It it's a slight echo, chances are there are no cracks.
Ceramic Repair
Ceramic repair can make a difference if the piece is part of a hard-to-find collection. Ceramic Restorers can do a very good job in restoring a piece to appear as though original. Only an honest dealer will be upfront about that if they are aware of it. These pieces are difficult to discern.Restored or repaired pieces should not be valued as high as an original intact piece. Restored pieces don't make a good investment for possible resale, but very special pieces can certainly be improved and may be worth restoring.
Brown spots in porcelain may show they are older pieces, but they have little value. Even when bleached, it's often difficult to remove entirely. Only purchase these pieces if you love them. They have little value as an investment.
A collector should always ask questions of the dealer or auctioneer, rather than assume the piece is in original condition, especially given the value and the investment she is about to make.