I'm curious, what everyone considers far enough in the future for your code. Eg. are you willing to write code that puts nanoseconds in a 64 but number? That is "only" 584 years after epoch. Would you consider that ok?
500 years is pretty different. Odds are that computing will look nothing like what we know today. Our software will be long dead.
And if it isn't, there will be yet another Y2K bug in 500 years' time, and they'll solve it. Just like we keep solving it.