Decoupling caps and PCB layout
When it comes to the finer details of pcb layout.
Here is a example of a recent board of mine, and I have highlighted three of the decoupling caps.
The MCU is a LQFP100 package and the caps are 100nF in 0402
packages. The vias connect to ground and power plane.
The top cap (C19) is placed according to best practices. The other two are not. I have not found any problems. But the board has never been outside the lab.
My question is: How big a deal is this? As long as the tracks are short, does it matter?