Buying guides

Contract or SIM only?

A pay monthly contract bundles the handset cost into your bill, usually over 24 or 36 months. It spreads the cost, but you are locked in and the total is nearly always higher than buying the phone outright and pairing it with a cheap SIM. If your current phone still works, a SIM-only plan is the fastest way to cut your bill — often to under £10 a month.

How much data do you actually need?

Most people badly overestimate. If you are on Wi-Fi at home and at work, 5–10GB a month covers messaging, maps, music and a reasonable amount of scrolling. Heavy video streaming on the move is what burns through an allowance — if you watch an hour of HD video a day on mobile data, budget 100GB or more, or go unlimited.

Watch the mid-contract price rises

Most UK networks raise prices every spring. Some use a fixed pounds-and-pence increase, others a percentage linked to inflation. Over a 24-month contract that can add meaningfully to what you pay, so factor it in when two deals look close — and check the small print before you sign.

Virtual networks are the same masts for less

Giffgaff runs on O2, Smarty and iD Mobile run on Three, Voxi runs on Vodafone. You get the same coverage as the host network, usually at a lower price, in exchange for lower priority at peak times on some plans and less hand-holding on customer service. See our network comparison for who runs on what.

Check coverage before you switch

National coverage percentages hide big local differences. Before you commit to a new network, check its coverage map for your home, your workplace and your commute — and remember you have 14 days to cancel a contract bought online.