[dragontamer]

> The sibling comment is too specialized, I feel. It depends on what you want to do. If you just want to connect a few components together, you can learn the required skills in a day, watch some KiCAD videos.

That's fair.

Lets put it this way: if your circuit works on a breadboard, you don't need to know anything about PCB design. The PCB will pretty much always be better than the breadboard.

Things get troublesome as you enter mixed-signal (analog + digital), or high-frequency.

[stavros]

Agreed, but you still need to know a ton of things that seem hard when you haven't done them before. Even exporting the Gerbers, or the BOM for assembly, or any of those things seemed too hard to me before I did it for the first time, so I don't want to underestimate people asking "I want to connect a few components into a custom PCB, how do I do it?".