When I first started my engineering career, I did not know much about configuration management. In fact, my introduction to configuration management was more about what happens when it is missing.
I had been making a series of iterations of the product, without keeping track of each iteration of the product documents. Eventually an iteration of the product quit working entirely, and I had to trace the previous incarnations. This was not a very good way to learn about the consequences of not managing the configuration of the product.