Start with your real usage, not the marketing
Open your phone's data settings and look at the last three months. Most people use far less high-speed data than the plan they pay for, because unlimited is sold as insurance rather than need.
Write down the highest month, not the average. That is the number your plan needs to cover comfortably.
Decide which network you need
Coverage is decided by the towers, not the brand. A $25 MVNO plan on Verizon towers uses the same masts as a $65 Verizon plan; what differs is data priority during congestion and extras like hotspot.
Ask neighbours or colleagues which network works in the places you spend most time, then filter to plans on that network.
Compare the total, not the headline
Check whether taxes and fees are included, whether the price assumes autopay and paperless billing, and whether the first months are a promotional rate that later rises.
For families, compare the total monthly bill for the number of lines you actually need, since per-line pricing changes with line count.
Check the switching details
Confirm the plan supports your handset, whether it needs a nano-SIM or offers eSIM, and that you can keep your number.
eSIM plans can usually be activated within minutes, which makes trialling a cheaper carrier low risk.
This guide is general information, not advice about a specific account. Always check current terms on the carrier’s own website before signing up.