Why YSK: If you have digital data that is important, (family photos, crypto keys/wallets…). Back it up and prevent permanently losing it.
3 different places its saved to, (iPhone, ICloud, laptop, Facebook, Google, Camera SD, Flash drive…).
2 different media, I would consider iPhone and iCloud the same. Buying two External Drives of the same type and brand too. Why? Consider losing your Apple account or the drive model fails in a year.
1 off site copy. If all your copies are in your house, a flood, fire, tornado, hurricane, EMP… would lose every thing.
0 time to waste. (My own personal add). Do it now. Procrastination is dangerous and is the biggest regret for when things go sideways.
Use a password manager.
I’ve used Bitwarden for years to generate passwords for any account I need to create.
It works well on your phone and has Chrome and Firefox extensions to easily autofill your passwords for login.
A paper trail for your master password, somewhere secure is good. Password manager companies have been breached in the past (see LastPass), so rotating your passwords and signing up for breach alerts will help save you from disaster.