A socket set is the backbone of any tool kit, but the labels hide three separate decisions: measurement system, drive size, and socket depth.
SAE or metric
Metric fasteners dominate modern vehicles, appliances, and imported hardware; SAE still shows up on older machines and US-made equipment. If you work on both, buy a set that includes both — a mismatched socket rounds a bolt head fast.
Drive size
1/4-inch drive suits small fasteners, interior trim, and tight spaces. 3/8-inch is the everyday size for engine bays, furniture, and general assembly. 1/2-inch drive handles suspension, plumbing unions, and anything that needs a breaker bar.
Shallow vs deep
Shallow sockets fit almost everywhere; deep sockets clear studs and nut runners. Most kits include shallow only, so add a deep set in your most-used drive size.
Six-point vs twelve-point
Six-point sockets grip more of the flats and are far less likely to round a rusty bolt. Twelve-point sockets engage faster on undamaged fasteners but slip more under load. Buy six-point first.
What to buy first
A 3/8-inch, six-point, metric and SAE set with a ratchet, two extensions, and a universal joint covers most jobs. Add 1/2-inch impact sockets only when you buy an impact driver.
Shop hand tools and socket storage.