So, my trusty Nexus 5X gave up the ghost suddenly on me. Given that it is an Android device, I was not worried about losing things like my contacts and photos, or even my apps as Google does a pretty decent job backing those things up.
However, there was one application I use which does not get its data backed up. FreeOTP which is a One-Time-Password application for Two Factor Auth. This allows me to have another layer of protection on web sites past my password.
Most sites which have this option will allow you to either have a list of one-time use codes to get in to reset in case something happens to your phone (like me), or will let you set it up on multiple devices, like your phone and your tablet.
Then, there are those that do niether. And those are a pain to recover from. 🙂
Always get the list of codes (if avalible) and store then somewhere that you can access if your phone ever dies or gets lost. And, try to set up a second device if you can.