Ask what is unlimited
The word can describe UK data, standard calls or specified applications. Read the relevant inclusion and its exclusions. An app benefit can treat adverts, external links or calling functions differently.
Ask what remains separate
Roaming, premium numbers, international calls and hotspot use may have their own rules. A broad domestic description cannot replace those sections of the terms.
Ask what feels usable
Coverage, congestion, upload capacity and latency influence everyday performance. Unlimited volume is not a speed commitment. Several ordinary months of actual usage are more useful than choosing on a headline alone.