Why the market is good
Teaware does not wear out in the way most goods do. A porcelain pot from fifty years ago pours exactly as it did when new, a glazed cup is unchanged, and a well-made stoneware pot outlives several owners. Meanwhile complete tea services and single pots without their lids turn up constantly in general sales at a fraction of retail because they are unfashionable rather than faulty. This is the one part of teaware buying where the economics genuinely favour the buyer.
What to check, in order
Completeness first — a pot without its lid, a gaiwan without its saucer, an infuser without its basket. Then structural condition: run a fingernail across every surface, hold the piece to the light, and tap glazed ceramic gently, because a piece with a crack rings dull rather than clear. Then the working properties: lid fit, spout bore, filter condition, and whether it empties. Then staining, which is cosmetic on glazed ware and is history on unglazed ware.
The unglazed problem
A second-hand unglazed pot carries whatever it was used for, and you cannot know what that was. It might have held one oolong for twenty years or it might have held coffee. Smell the dry interior, which tells you a surprising amount, and assume that a strong smell will not fully come out. This is the one category where second-hand carries a real and unfixable risk, and it is worth paying more for a used pot with a known history than less for one with none.
What cannot be established
Age, maker and material on unmarked or stamped ware, for all the reasons set out in the collectible-clay guide. Whether an old enamel lining is intact under staining. What a cane handle has been through. Whether a metal vessel’s lining has worn. TeaHQ makes no assessment of materials beyond how they behave in use and does not offer a view on old glazes or old linings in any other respect; if that matters to you, the answer is to buy new.
What is worth buying used and what is not
Worth it: glazed pots, porcelain cups and gaiwans, trays, cast iron, silver and brass, catering steel, complete western services. Not worth it: bamboo, which is a consumable and will be brittle; cloth filters; anything with a perished silicone seal you cannot replace; and unglazed clay from an unknown kitchen. The line runs roughly between things that are inert and things that have absorbed something.