Trying to get the PCB ordered on my prototype "DuckLight." The first Eagle layout looked pretty good, but it seemed possible to shrink the board's footprint until it was only 2xAAA wide. Which you can run on, but it runs the LEDs a little cold.
Anyhow, I shrunk the layout and ran traces by hand. I was also conscious of the potential difficulties in soldering SMDs so I made a point of holding the traces far outside of the pads of those parts. So that took a couple of evenings. But got it down to one via (well, I also ended up omitting a duplicate VCC on the second header. It would have required multiple vias in order to get the connection.)
I used a part with internal connections (a tactile switch) as a jumped in one spot, and Eagle kept flagging it. So I went to the forums for the first time with a question. And it turns out not only have lots of people asked about this, there is no current solution.
But then I went to order the parts to make sure the ones in the CAD were actually available stock. I'd used the SparkFun Eagle library in several places, and you'd think this would be a shoe-in, right? But no. The part in their library doesn't actually have an analog in their store.
They did have something in their store that I could modify the package to, however. And after a bit of struggling re-routing around the new (and larger) dimensions, I had confirmation of available parts.
The final DRCs, and Eagle starts throwing up mask errors. Turns out that, yes once again, many of the library parts I was using have a silkscreen that goes over the copper traces. Which can be a problem at smaller fab houses that don't have the software to fix this on the fly. So back once again to the package designs, now to edit all the silkscreens.
Nice of various people to make libraries available to everyone, but really, could they adhere a little closer to reality?