I'm new to nostr and the whole decentralized world, so my question might be trivial.

When the time comes to change the device would you lose the network you built? Could you sign up to the new device with the same use name and still be verified?

One issue I see for less developed countries, like Brazil, is that cell phones are stollen all the time. It's not rare cases of people buying a new phone to have it stollen the next month. I device based identification would be very impractical for this scenarios.