I sometimes keep U.S. grocery store eggs for months, in the fridge (I'm a bachelor living alone and don't eat eggs regularly) -- they totally last for months without going bad, all the time. Like I've kept eggs 2-4 months multiple times, months past the "sell by" date, in the fridge as we do in the U.S. -- have NEVER experienced a bad one.

Doesn't matter if they float either, that just means there's more air under the shell, which does mean they're older, but it doesn't mean they've gone bad.