This is true only if your product is designed to tinker. Or you generally have to replace plug and play parts. When desktops came along many people wondered if

This is true only if your product is designed to tinker. Or you generally have to replace plug and play parts. When desktops came along many people wondered if they could be serviced as easily as TVs. The answer turns out to be simple, they don't have to be. If the repair + component costs turn out to be in the same ball park as replacing the plug and play part, you don't have to service individual PCBs. To give you a example, recently I had a broken Dell Monitor. Got it fixed in 20 mins at a local service store. Apparently the technician simply removed the whole PCB and put a new one in its place. And there were only 3-4 such PCBs. You only need to be as intelligent as the abstract interface allows you to be.