> Or instead of iterating 5 times, you take your time and do it right on the 2nd attempt, figuring it out in 1/3 of the time. Hurrying only leads to mistakes.

In an abstract sense this is true, but there are some fields were you do just have to do it again, and again, and again. I know an exceptionally smart biochemist who routinely has 16 hour days. There's no substitute.

In my own field, someone who would later go on to win a Nobel for the work, was working on something that simply required a huge amount of time and iteration to get right. This is often the case.

This is not true in all fields, of course. I just want to caution against extrapolating from experience in one field to all PhDs, which is the sense I get from a lot of comments in this thread.