When you get a board, assuming you have no complaints about it’s functionality, to what degree to you judge them/the design based on their care with layout? I definitely judge VERY harshly on this (I made a new board rather than trying to hunt down the manufacturer of a board and try to buy 100 of their design because I didnt like how they laid it out. Sure enough, I later discovered several dreadful design decisions that demonstrated that yes indeed, this was his first rodeo, and his design was unfit for purpose. Not that the other design I am using in place while I wait on my boards IS fit for purpose; it sucks in other equally serious ways… but it’s cheaper and readily available)
- no ground plane, or ground plane only on one side.
- traces at angles other than multiples of 45 degrees, traces going away from a via where the trace turns within a fraction-of-a-tenth-of-an-inch of exiting the via) - things that indicate lack of care/polish
- traces routed in unnecessarily circuitous ways, or stubs from where they re-routed and didn’t finish deleting the old trace, or traces changing thickness for no reason.
- Halfassery like the purple USBTinyISP devices (look on the underside around the USB connector - they switched part package for the USB connector without redrawing the ground plane! My guess is they were modifying the gerbers directly because they didn’t have the design files)
- Traces that could be parallel not lined up
- Vias in close proximity arranged blindfold-and-dartboard style, instead of lined up
- Reference designators or silkscreen markings cut off by pads or edge of board, or where they clearly didn’t bother to smash and reposition them. Admittedly, eagle makes it very easy to do this poorly)
- Reference designators numbered weirdly (means they didn’t panelize it correctly)
- reference designators with a $ in them (indicating both that he didn’t do the library right in eagle AND didn’t correct the names - even when I was noob, I didn’t let those slip into anything I shipped… or even fabbed for that matter)
Basically, as a designer, the kind of things I did in my early designs when I didn;t know how to use Eagle. If I did that when I was inexperienced, what ELSE doesn’t the designer know how to do? If their design is halfassed like I describbed above, I suddenly no longer trust him to do decoupling right, or do… a lot of other important stuff… right.
Also, as an aside, looking back at my old designs is cringey, like reading the term papers I turned in in highschool (“Good god, what kind of moron wrote that?! He has no clue how the world works, and his grammar is vile to boot! And another thing…(snip)… just awful, who the heck wrote something like this, make sure he never has any responsibility! And maybe remove some of his body parts so he can’t repro… What, you say it’s mine? Oh dear, I thought it looked familiar”)