I've had my phone stolen while traveling, and I can't say how much I despise any system that uses a phone number for authentication.

Go figure, you can't get a SIM card sent to you from the US to Europe, meaning that you potentially lose:

* Access to messenger apps and chat history

* Access to your bank account (with a special nod to Citi)

* Access to your email account if it uses "2FA" with a phone (looking at you, Google)

* etc

Given that my bank cards and laptop were stolen along with the phone, I've had a Very Fun Time™ dealing with all these systems.

You can port your phone number to a voip provider if you will be out of the country for a while. Use a sip phone app, and the "transport layer" sim that you happen to use will have nothing to do with the phone number that is intermingled with your identity.

This is way too much hassle even for me as a techie.

And something tells me short-code SMS receipt (which is what banks use for 2FA) is not going to work well anyway.

If you don't need it, you don't need it. But for the record:

a) Porting your number takes about as much effort as moving between mobile phone providers

b) Setting up a sip app on your phone is trivial (server, username, password) - I'm generally a fan of Acrobits Softphone

c) My voip provider has an sms <> email gateway, so my bank (and other sms based) mfa lands in my gmail inbox

FWIW, Telegram actually handles this pretty well. You just have to have loged in on another device while you still have your phone. You can use that other device to deauth your lost or deactivated phone and auth new logins on other devices.

Sadly I didn't use Telegram for 6 months and when I went to use it I found out they had a 6 month timeout on your login and it basically wipes your stored credentials after 6 months :(