While my phone was being repaired I ran into a predicament. The only way I could log in to my Google accounts was by authenticating via an SMS code which I wasn’t to get without an SMS code. Additionally, I never bothered to actually write down the backup codes thinking I’d never need them so I was stuck in the envious position of being Google account free for 4 days.
Luckily, I had two things going on that made the loss easily manageable. One was that I shared my personal calendar with my work account so was able to see (and create) everything I needed through my work account. And two - I’ve been forwarding all of my email from Gmail to Fastmail since March of last year. The only real frustration was not being able to search through my email history nor use the chat. Otherwise it was barely noticeable.
I definitely got lucky so the lesson here is that it’s impossible to predict what’s going to happen and you should just deal with the annoyance of the backup codes. Google also provides the Authenticator app which is another way of supporting two factor authentication. None of these is as simple as just not having two factor authentication but I think it’s a must have - especially for a primary email account which is linked to every other account - including your financial and social media accounts. Losing access to your emails makes it very easy to reset the passwords on those and there’s no excuse in not enabling two factor authentication.