Always charged
When you are in another country, you might feel lost sometimes. As long as you have your phone, you can usually get around. After all, they were made for, making our lives easier, wherever we are.
That is why you should always have it fully charged. But even if you left it charging all night, with all the apps you use while traveling and photos you take, your battery will drain quickly. Remember to carry a portable charger with you; it can save you from your phone dying and a bad situation.