Making a PCB is very simple; it does not consume a ... but needing multiple copies of the same circuit is the reason that forces many away from using protoboard. After making your first circuit ...

No user-serviceable parts inside? Give me a break! The head unit is tough to get to, but the PCBs within the chassis use ...

You hold in your hand a circuit board from a product you didn’t make. How does the thing work? What a daunting question, but it’s both solvable and approachable if you know what you’re doing.