I am a beginner with electronics and microcontrollers in general and is still learning a lot.
I own a few varieties of the Arduino family boards and built a few projects using ATmega and ATtiny family chips using breadboards.
Most of the times I will build a little circuit like using a shift register some LEDs and a pot for example to test and learn.
After a while I need the breadboard for another project so I end up drawing a schematic using KiCAD, Eagle or Fritzing and save the schematic file alongside my code.
After some time passes I would like to tinker a bit further so I load the schematic file and rebuild the whole circuit again on my breadboard.
I am at a stage where I don't want to just buy a new breadboard for each project because breadboards are expensive and not always that reliable, plus I probably need the practice to learn how to solder circuits properly. I thought about buying Arduino proto shields but even then it is still a bit expensive. Also I don't want to buy a Arduino board each time I want to prototype a project when I can simply buy the chip and a few passive components for a fraction of the price.
So I decided to build my own Arduino/AVR development board using very inexpensive protoboard with some headers to stack my projects on top. This gives me the flexibility to re use the development board for lots of different projects.
Essentially I am reinventing the wheel here and I am aware of that, but it is a much cheaper wheel and from which a lot more experience can be gained.