That sounds a bit extreme? True, estimation is hard, but surely we can differentiate between 1-2 day work, 1-2 week work and a big scary project with a lot of risk. That's what T-shirt sizes are for.
And if a bug in a library stops you from completing your work so you have to develop a workaround, and adds several days to your “1-2 day task”? The estimate is wrong.
There are simply too many unknowns in other libraries and systems to be accurate.
