This is one of my favorite quotes by Heinlein from the book Time Enough For Love. Essentially this is giving his point of view between focusing on a particular area vs. being a jack-of-all trades, so to speak.
I can understand the value of specialization to a point, but I think when you become too much of an expert, your ability to see the bigger picture, connect ideas, and think outside the box diminish. The perfect balance, from my perspective, is to have just enough understanding of an area to grasp the major concepts and effectively communicate with true experts in the field. Anything beyond that loses value because you slowly lose your ability to provide a unique perspective. Below you can find the full quote from Heinlein:
“A human being should be able to change a diaper, plan an invasion, butcher a hog, conn a ship, design a building, write a sonnet, balance accounts, build a wall, set a bone, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, analyze a new problem, pitch manure, program a computer, cook a tasty meal, fight efficiently, die gallantly. Specialization is for Insects.” - Robert A. Heinlein.