Someone might answer: "Half an hour." "An hour." "90 minutes." "45 minutes." "Soon." "Right before lunch." "Right before Jeopardy starts." Different people give different answers under different circumstances. None of which is really relevant to the "piece of string" saying. It's a saying; trying to tell the entire English-speaking population that they should go back several generations and change this particular saying to be more acceptable to your sense of logic is really a futile effort. ChickenFreak
Oh no. My usual answer to the question, 'How long will it take you to that, buddy?' is: 'No idea. How long's a piece of string?'
I've read that you're not a native English speaker, Cacian, so I understand your frustration on this. The "Aye", to me, can be understood as a flippant reply which means: Something like that, or Maybe, or Near Enough, or No idea at all really, I just have to answer you, or Are you really that stupid? Tough going, but we can persevere!