The most useful single check on any piece of case furniture, and it takes five seconds. Pull a drawer out and look at the joint — hand-cut and machine-cut dovetails are unmistakably different once you know what to look for.

A hard chronological floor. Curved arcs mean a circular saw, and circular saws cannot predate their own invention, so the marks put a date before which the timber cannot have been cut.

Mass-produced from the 1820s onward by pressing molten glass into a mould, which made patterned glass affordable for the first time. It is routinely sold as cut glass, which it is not, and the difference is in the sharpness of the edges.

A printed pattern transferred from an engraved copper plate to tissue and then to the ceramic, invented in the 1750s and dominant through the nineteenth century. The backstamp is where the dating happens.

The first fully synthetic plastic, patented in 1907, and a significant collecting field in jewellery, radios and kitchenware. Two simple tests separate it from later plastics.

British hallmarking is the most informative marking system on any antique — a full set of marks gives the metal, the assay office, the year and the maker, with legal force behind it. American silver is far less regulated and gives much less.

Domestic lighting between roughly 1860 and rural electrification, so they exist in enormous numbers. The burner is where the dating and the value are, and it is the part most often replaced.

A large and active collecting field where the useful dating evidence is on the base — the gate mark, the heat ring, and the maker's lettering.

Finish type gives a rough date and, more usefully, tells you whether a piece has been refinished — which frequently matters more to value than the age does.

The case and the movement are separate objects and were sold separately. They are frequently mismatched, and the serial number on the movement is what dates the watch.

Dated primarily by the fabrics rather than the pattern, since patterns were copied for generations. Dye chemistry gives some usefully hard boundaries.

The single most systematic dating problem in the whole field, because the seam tells you the manufacturing method and the method has a known chronology. Follow the seam up the bottle.

The back of the card dates it more precisely than the front. Postal regulations changed at known dates and the layout changed with them, which gives a clean chronology.

A large collecting field where the signature does most of the work. Clasp and finding types give a rough date, and the maker's mark gives value.

Dated the same way as furniture — by construction and hardware rather than by style, since box forms were reproduced continuously.

The physical format dates the photograph closely, because each process had a commercial period and they barely overlap.