Eastern US here. I will get those errors a few times a week but I'd say 80% of the time it works on a refresh and most of the rest of the time it's back within 30s.
Also very common for when you post a comment that it appears to not have posted it and returns an error, then you retry multiple times and get multiple comments posted. And even if you don't get hit by one of those outages, they tend to get saved in the comments from everyone else having hit them.
For me in the EU it fails once a year or so and only on the few occasions I use reddit's own webpage instead of a third party app or web like libreddit.