What length of fast is indicative of the ability to do any length of fast, in your opinion? 5 days? 14 days? 21 days? 40 days?
When it comes to fasting, we have people doing all sorts of lengths, from 24 hours all the way to many months.
A 3-day fast is a different game from someone doing 16–8. A 14-day fast is a different beast that a 3-day faster probably can't face easily.
But is a 40-day fast really that different from a 30-day fast? I don't think so.
So at what length do you think someone reaches the point where, if they can do that, they can do pretty much any length of fast?
At what point does fasting duration stop being a meaningful indicator of someone's ability to fast longer?