The saying that “good design is obvious” is pretty damn old, and I am sure it took different shapes in the previous centuries. It referred to good food, music, architecture, clothes, philosophy and everything else.
We forget that human mind changes very slow, and the knowledge you have about human behaviour will not go old for at least 50 years or so. To make it easy for you, we need to keep consistent with a couple of principles that will remind us of how to design great products. We should be told at least once a month about these small principles until we live and breathe good design.
The human brain’s capacity doesn’t change from one year to the next, so the insights from studying human behaviour have a very long shelf life. What was difficult for user twenty years ago continues to be difficult today — J. Nielsen