Binoculars are the one piece of kit every birder uses on every trip. The two numbers on every model describe magnification (8x or 10x) and the diameter of the front lenses in millimetres (32 or 42).
An 8×42 is the classic all-rounder: bright in forest shade, easy to hold steady and wide enough to follow a warbler through the canopy. A 10×42 suits open country, wetlands and seawatching, where extra detail at distance matters more.
Try before you buy
Hold a pair for at least a minute. Check how quickly you can find a bird, whether the focus wheel is smooth, and whether the eyecups sit comfortably, especially if you wear glasses.