Reading the offer
Start with the actual line count. A family per-line figure can be irrelevant for one person. Then identify the base service, required payment method, qualifying discounts and any time-limited extras.
Managing a household
Give each phone its own record of balance, credits and authorized user. Ask what happens to the remaining lines if someone leaves. The account holder may have payment responsibility for devices used by other people.
Limits behind unlimited
Look separately at high-speed data, hotspot, video and travel terms. Do not assume the same rule governs on-phone streaming and a tethered laptop. Confirm how performance may change when an allowance is exhausted or a cell is busy.
Before changing a tier
Check whether existing device credits or bundled benefits depend on the current tier. Ask for the effect on the full account, not just the edited line. Keep a dated confirmation of the change and review the next statement.