I have an iphone and used to have a trust wallet - so far so good
One day my iphone decided to crash so I had to reset the phone, now me being not that clever had backed up my wallet as you should do but saved it locally to my phone, ok so now there's a problem, I had signed up to a few ICO's etc and added some of my own money to the wallet, but because I hadn't backed the wallet up to itunes the whole data was lost, I lost overnight 8 months of work.
Hi!
I also use different wallets on my iPhone - Jaxx, Trust, Loaf, O3 just to name few. I wasn't even aware that I should back them up anywhere.
The most important thing are the private keys, as many stated.
Never take a screenshot, don't upload them to your cloud storage.
Just plain and simple, write them on a piece of paper.
Have few little notebooks with all of your emails, codes, passphrases, and have them stored in different places.
Also, really important - notify one person about one of them, in case of your death. A bit morbid but really important.