US CERT has some excellent guidelines for protecting for Mobile Devices during the 2018 holiday season

https://www.us-cert.gov/ncas/tips/ST11-001

Your smartphone, tablet, or other device is a full-fledged computer. It is susceptible to risks inherent in online transactions. When shopping, banking, or sharing personal information online, take the same precautions with your smartphone or other device that you do with your personal computer — and then some. The mobile nature of these devices means that you should also take precautions for the physical security of your device (see Protecting Portable Devices: Physical Security for more information) and consider the way you are accessing the internet

https://www.us-cert.gov/ncas/tips/ST05-017

While computers provide increased features and functionality, they also introduce new risks. Attackers may be able to take advantage of these technological advancements to target devices previously considered “safe.” For example, an attacker may be able to infect your cell phone with a virus, steal your phone or wireless service, or access the data on your device. Not only do these activities have implications for your personal information, but they could also have serious consequences if you store corporate information on the device.