My physical library used to be as complete and varied in perspective as I could make it. Then, with the advent of computers, it expanded to nearly 10,000 volumes in digital format.
At this stage of life, I really don't need (or want) my shelves filled with nonsense. So, by and large, my physical library is becoming more consistently and overtly Reformed. I have kept weeding out the chaff and heresy (e.g., Tillich, Pittenger, charismania), allowing the heresy for "research" purposes to exist in digital form where it can be readily . . . er . . . ah . . . well . . . researched. This saves a lot of space and weight (3,500 or more volumes eliminated in the last decade alone).
As I age, the ink and paper books I want near me are the ones by Calvin, Turretin, the Puritans, Hodge, Bavinck, Berkhof, Grudem, Muller, Beeke, and the like. Once in a great while my ego misses the sight of several hundred feet of missing books reminding me that at one time I looked educated. My wife, on the other hand, loves it and wishes a greater "pruning" would take place.
Other than Spurgeon and Wilber Smith, who could honestly say they have read and know all of the books in their thousands of book libraries?