My most costly mistake... a few years ago, I did some technical drawings installing a lot of fiber optic cable. I used our standard cable length estimation technique as usual, but neglected to consider the condition of the cableways or the propensity of this particular installation team to waste vast quantities of trunk for no apparent reason despite clear knowledge of how short they were. To make matters worse, this was all specialty long-lead-time stuff that we ended up having to haggle and buy from a partner/competitor who did NOT want to sell it to us. Ended up with a shortfall of about $1 million worth of fiber optic work until it was all said and done. It's amazing- hundreds of sheets of meticulously accurate drawings, but make one tiny $1 million error on the material list and catch nothing but hell for it! Took me a long time to live down that one! Luckily for me it was a high dollar job, and there was some griping but it paled in comparison to some OTHER problems on that job, so I never really caught much back from it except from the other engineers [Linked Image]

Also, on the same job, I made a copy/paste error and was 1 number off on the part# on material list- accidentally ordered 6,000 of the wrong part. Was supposed to be $5 end caps, but accidentally put the number for tee couplings, which ran about $50 apiece. oops! We were able to fix that one though, heh.