Today's hobbyists and small-time electronics builders have more options for producing durable, professional-looking printed circuit boards (PCBs). Printed circuits are more flexible in size, hold up better in adverse conditions, and cost less if you make more than a few.
Especially when you're working with plug-in style breadboards, the breadboard itself determines the size of the final circuit. Since breadboards are meant to be reused, they come in a variety of sizes, but you don't cut them. A custom-printed circuit, on the other hand, is exactly the size you need. You determine its size when you create the board pattern. You can even create odd-shaped boards to fit a custom enclosure.
While a well-made prototype can be rugged, the physical construction of a PCB is superior. The copper conductors on a printed circuit are bonded to the board. A prototype is usually done with point-to-point wiring, which can come loose with vibration. Circuit board components are always soldered in, which contributes to durability. In addition, on a printed circuit, it's easy to add holes for screws and other mounting hardware.
If you're making just one or two of a particular circuit, it might not be worth the effort of designing a PCB layout. But for simpler circuits, making even a few PCBs can be less expensive than hand-building every one on a prototype board. As quantities go up, the PCB becomes more attractive. With today's PC software, you can make printed circuits at home or send the design to a custom manufacturing shop to make a few.
Since most printed circuits are designed in software, the program arranges the parts for best performance. As a side benefit, the board has a neat appearance. Parts are spaced evenly, and traces are symmetric and uniform. You can add silk-screened artwork and text to the board. The reduction of point-to-point wiring makes for a sleeker, more professional appearance. Prototype boards are meant to be flexible, but not necessarily professional-looking.