Is unlimited really unlimited? Compared with fixed GB

Most traveller unlimited plans include a set amount of full-speed data per day; once it is used the line keeps working but at reduced speed until the next cycle. The figure and the way the cycle is counted differ from plan to plan, so it has to be read on the page for the plan you are buying. If that page does not state it, ask before deciding.

The data connection stops. The line stays on the phone but carries no traffic until you top up, where the plan allows it, or buy another plan and install it as an extra profile. WiFi still works in the meantime. Checking the remaining balance once a day is the simplest way to avoid meeting this at the worst moment.

Check the hotspot terms before anything else: some unlimited plans limit how much can be shared or do not allow sharing, while fixed-GB plans usually draw from the same pool without a separate rule. If sharing is a real part of the plan, estimate with more headroom than feels necessary, because laptops and tablets consume far more through automatic updates than a phone does.

It depends on the speed that particular plan drops to, which differs by plan and by destination network, so it cannot be promised here. The safer approach is to download offline maps for the area while you are on WiFi; then navigation works whether the speed is reduced or the signal is poor.

You can buy another plan and install it as a second profile on the same phone, provided there is storage left for it. How many profiles a handset can store, and how many can be active at once, depend on the model and the OS version. Do not delete the old profile until the new one is genuinely working, because the deletion is usually permanent.

Not in itself. Speed comes from the destination network the plan uses, the state of the cell site where you are, and how busy it is at that moment. If two plans ride the same network, the full-speed tier does not differ because of the plan category.