The act of sharing does not add a meaningful amount by itself; what adds up is the behaviour of the devices that join. Laptops and tablets download updates, sync cloud folders, and play video at higher resolutions than a phone does, so the total is usually far above phone-only use. The fix is to mark the connection as metered and pause background work before connecting.

In most cases the laptop feeds power back into the phone while the cable is in, but how fast — or whether it happens at all — depends on the laptop's port, the power that port can supply, and the laptop's own power settings. For a genuinely long session, plugging the phone into a mains adapter is still the more dependable route.

Separate the two layers. First, can the phone reach the internet by itself? Turn Wi-Fi off on the phone and load a page there; if that fails, the problem is the underlying connection rather than the sharing. Second, does the plan permit sharing at all, which depends on the supplier and that particular plan — re-read the plan's details, and if it is still unclear, message the team on LINE or by email with the handset model and what you are seeing.

The maximum number of simultaneous devices is a limit of the handset, not of the plan, and it differs by manufacturer and system version. The hotspot settings screen usually lists what is currently connected. In practice, the more devices attached, the thinner each one's share of throughput and the faster the host phone's battery goes.

If a cable is at hand, use the cable. Video calls are more sensitive to inconsistency than most other work, and the places people take calls while travelling — cafes and hotel lobbies — are exactly the places where the Wi-Fi band is most crowded. A cable removes that variable, and helps with battery and heat at the same time.

Once the switch is off, the radio that was broadcasting stops, so that draw ends. On some phones, though, the hotspot turns itself off after a period with nothing attached and then comes back when a device that remembers the password asks to rejoin. If that is not wanted in a public place, switch it off deliberately and review the list of previously connected devices from time to time.