Enable password protection and auto screen lock on your phone.
Our phones are small and always with us. This puts them at a high risk for loss and/or theft.
They also contain a near 100% digital replica of everything we consider private and personal. Emails, address book, photos, social media accounts, banking apps, travel apps, health apps, and the list goes on.
Losing a wallet probably means having to call 4-6 phone numbers to cancel/re-issue a few cards. Losing an unlocked phone is a nightmare.
Mobile operating systems offer so many different ways to lock your phone, there really isn't any excuse to not do it.
Depending on your phone you can lock it using:
Digits
Letters
Pattern swipes
Picture swipes (BlackBerry)
Facial recognition
And even your finger print !(when it the last time you forgot your finger print 
)
Just lock it
***Edited to add labels***
