Which knitting needles to buy

• Wood and bamboo — Grippy. Stitches stay where they are put, which is what a beginner wants and what somebody working fast finds slow. Warm to hold, and they can snap in the smaller sizes.
• Metal — Slippery and fast. Stitches move freely, which is efficient and which means a dropped stitch drops a long way. Cold at first, and noisier.
• Plastic and resin — Between the two, light, and the usual choice at very large sizes where metal would be heavy.

The pairing that matters is material against yarn. Slippery yarn on slippery needles is how stitches escape, and grippy yarn on grippy needles is how a project becomes hard work. A beginner using ordinary wool is well served by wood; somebody knitting with silk or a smooth cotton will find metal fights them less.

Straights

Flat pieces onlyWhat everybody pictures. Limited by their own length — a wide piece will not fit on them — and awkward on a train.

Circulars

Flat pieces and tubesTwo tips joined by a cable. Work back and forth for flat, or join into a round for a tube. The general-purpose answer, and they take the weight of the work on the cable rather than on your wrists.

Double-pointed

Small tubesSets of four or five, for anything too narrow to go round a circular cable — sock toes, glove fingers, the crown of a hat.

If you buy one thing, buy a circular. It does everything a straight pair does and a category of things they cannot, it is easier on the hands with a heavy project, and the cable length only limits you downward rather than upward.

The cheap sets sold to beginners contain a wide range of sizes at low quality, and the low quality shows in the two places it does most damage: rough joins where the tip meets the cable, which snag every stitch as it passes, and cables with a permanent coil that fights the knitting. A beginner meeting either of those concludes that knitting is fiddly, which is a reasonable conclusion from the evidence and the wrong one.

The better first purchase is one good circular in the size your first project wants, and then more as projects need them. Interchangeable sets are genuinely excellent and worth buying — after a year, when you know which sizes you actually use and can tell a good join from a bad one by feel.