What should I ask before buying glasses for phone-free use?
Ask which exact features work with the phone absent, where their data is stored and how they receive new information. Also ask what happens when they reconnect. A general standalone claim is too broad to plan around.
Request a demonstration of the absent-phone condition
We would choose one task that requires a fresh result, not merely the last item already on screen. If the task is recording, establish how much of the workflow finishes before a phone returns. If it is an assistant request, establish where the computation and required data come from.
Write the condition explicitly: phone powered off, glasses available, internet route named or absent. Then record the operation and result. That is a reproducible description of phone-free behavior, unlike a demonstration where an unseen connected phone may still be providing the service.