Powering off your phone regularly, disabling Bluetooth when it's not needed, and using only trusted accessories are just some of the NSA's security recommendations.
Source: ADnet
Source Link: https://www.zdnet.com/article/the-nsa-advises-you-to-turn-your-phone-off-and-back-on-once-a-week-heres-why/#ftag=RSSbaffb68