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> after you finish the first 90% you need to finish the second 90% (I forget who said this).

I don't know who said it either, but I heard an alternate phrasing: "The first 50% of the project takes 90% of the time. But the second 50% takes the other 90% of the time."



I probably should've just Googled it as it was easy enough to find. According to Wikipedia [1], it was Tom Cargill of Bell Labs and it's called the 90-90 rule:

> The first 90 percent of the code accounts for the first 90 percent of the development time. The remaining 10 percent of the code accounts for the other 90 percent of the development time

[1] https://en.wikipedia.org/wiki/Ninety-ninety_rule


That formulation doesn't work. The early work goes deceptively fast.


Fair point. IDK. I just think it's critical that the last part of the saying be highly unexpected.

I mean, if it starts with "The first 90% of the work takes 50% of the time ..." how do we maximize the unexpectedness of the punch line?

Cargill's original formulation, as Cletus quotes from Wikipedia, is best, I guess.




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