So one thing I think nostr has gotten really, really right: switching costs between relays are insanely low by design.
Discussion
switching anything is effortless, you can switch relays, clients and even pubkeys at will and they all work together
if relay.damus.io goes down I can think of apps that will be "down" because they aren't connecting to multiple relays
maybe during #NostrNovember we fix that part too