Mistake	How I fixed it
Connected the shift registers to low frequency MCU pins instead of high frequency ones	This turned out to not cause too much of a problem, but it results in more interference in the wireless signal when the lights change
Did not follow standard practices for reference designators on the PCBs	Did not fix
Placed a diode such that the diode legs would poke through and interfere with one of the stabilizers	Cut the legs short and carefully soldered it perfectly flush
Somehow forgot to add a bolt hole in the left switch plate despite running interference checks	Put the plate in a mill and drilled the missing hole
Missed the same bolt hole in the 3D print directly above said plate	Added the hole and reprinted it
Assumed the power switches I had had a circular mounting geometry instead of checking carefully and realizing it was the union of a circle and rectangle	Filed the corners off that part of the power switches
Forgot to consider whether any of my components would short against the bottom of the case	Added a layer of foam between the PCB and the case
Thought that soldering jumper wires to small SMD components by hand was a good idea	Spent a couple hours on extremely finicky and fragile work
Neglected to consider whether my soldered connections to the LED indicators would short against the top of the case	Taped a plastic film between the indicators and the case
Forgot to leave clearance for the wires going to the power switch	Reprinted battery holder with channel for wires
Neglected to consider wire management inside the case	Reprinted battery holders with clips to hold wires
Counted keys wrong and did not order enough hot-swap switch sockets	Bought more sockets
One key didn't work because a bent switch pin wasn't correctly inserted into the socket	Replaced switch
Neglected to consider before manufacturing the case whether a metal case would block a wireless signal	Drilled a hole in the case next to the antenna and added a plastic window there instead
Did not test how bad the signal integrity issues were before drilling that hole	There's not really a good way to fix this one, but things worked out in the end
Drilled the hole with a handheld drill, leaving me with quite non-circular holes	Tried to clean it up with a file, but not too much I can do about this one
My sheet metal bends' variation from the way they were designed was quite high. I should have practiced more on scrap metal.	Filed down the various tabs until they were even; tolerated the remaining imprecision
Did not realize I couldn't bend the angled corner tabs on a press brake	Bent them with pliers
When copying a part from the right to the left half, got my geometry mixed up	Reprinted parts
Used too thick of wires going to the power switch; excess strands that couldn't fit through the through holes on the PCB shorted to each other	Reworked with thinner wires
Numbered the status LEDs from the inside out instead of consistently left to right. Having "low battery" be the rightmost indicator on both halves would have looked better	Did not fix
Did not check which status LEDs were supported by ZMK before finalizing the case design	Gave up on charging indicator lights and made custom firmware to drive the rest
Tried to avoid having to understand the internals of ZMK by vibe coding the firmware extension	Learned what my code was doing well enough to fix it with help from the model