What’s stupider than making a stupid mistake? Here, let me answer that for you: Making the same stupid mistake a second time.
But you know, now that I think about it making the same stupid mistake a second time isn’t the stupider thing. Making the same stupid mistake a second time on the same project is.
Ten years ago at my old house I made a great lumber rack – simple, strong and even adjustable. It’s basically just four vertical 2x4s with a dozen horizontal lumber supports, three on each 2-by.All you need to do is measure carefully for the support locations, slip them over the 2x4s, then drill and bolt them into place. The key here is “measure carefully.” Well, I measured perfectly 11 times. The 12th time? Well, here’s what that looked like when I loaded up the lumber.
Yeah, I measured wrong there, although I don’t know how I messed up such a simple, repeatable, whole-number measurement. But the fix was easy – as I said, the rack’s adjustable. Just unbolt, move the support then drill and bolt again. (The slip-on support even hid the error.)
For my new shop I made this identical rack. And when I say identical, I mean that 100% literally. When I started stacking the lumber I immediately saw that not only was one of the supports too low, it was the same exact support that was wrong 10 years ago: The end support on the bottom row.
A dozen chances to make an error in a dozen different places, with an infinite number of possible actual measurement errors… and I make the same one. At least I’m consistent.