"What if we do this at the end of the project, how much longer will it take?"

Oh God! 😰 I see trouble ahead... this question has two implicit assumptions:

First, I feel the rough estimate we came up with is now taken as a commitment. Classic. 🤦‍♂️

Second, a system that has not even been fully designed has become a tangible reality in people's heads; as tangible as a couch 🛋️ that you want to place in your living room.

Sorry but I still don't know the exact dimensions of the couch; I'm not able to tell you how much longer it will be if we make it three-seats.
We didn't really know it was a two-seats before.
What the hell, I don't even know if it's a couch!
FOR GOD'S SAKE, WE DON'T EVEN HAVE A LIVING ROOM! 😫

How did we get here? (again...)