Becoming a great audio engineer, musician, or both is a lifelong process. Without any official finish line to cross, it can be difficult to see progress as your skills improve. One musician, Mr. Billy, set out to record, mix, and release 12 CDs over 12 months. Surely with that amount of work done in such a short amount of time there were some sacrifices in quality, but that isn't necessarily bad. If you strive for absolute perfection in every single mix, it may have a negative effect on your work capacity or even your own personal learning curve.
You can read the full article here: http://therecordingrevolution.com/2013/02/25/the-fastest-way-to-improve-your-engineering-songwriting-and-performing/