If I'm out of the country, can I still use my SIM card normally, or will it be restricted?
If you want to use roaming services or other features from your network provider, you will need to unlock the phone's SIM card.. Otherwise, you will have a lot of limitations while trying to activate roaming. However, if your carrier supports traveling and other services, you should be able to use most parts of the mobile SIM card normally. Still, it is recommended to unlock your phone's chip before traveling to avoid issues or unnecessary locks.