You can in most countries as far as i know. But in my example i quit my account (so made it prepaid essentially) and lost the SIM card, which means i lost my account forever. Now it waits for the simcard to invalidate and then will most likely sell the number again. It was a "easy number" (as in people remember that number after telling them once) so i assume it will be resold rather fast.

But just because you can does not mean people want that. Before it became normal to auth everywhere with phone numbers i happily changed my number yearly.

You'd be surprised. Number portability is a big pain in the arse for us (determining the network from an MSISDN is important in my industry) so it's always a nice bonus when we come across countries without it.

Most recently, Philippines: http://www.prefix.ph/smart-users/updated-philippine-mobile-p...

This is a really interesting example! Thank you, i obviously only thought about my rather small digitalnomad bubble & issues. But this is a good example for the same problem on a much bigger scale.

Once again it shows you cant just close your eyes and judge from yourself to others.

You can change them, you just have to change them in those services too. Same as with email, or any other authentication mechanism, really.

Just to offer the other side of this, I, on the other hand, have the kept the same mobile phone number since the beginning.