Good question, BetterSense;
This exact question is what influenced me most strongly in my selection of lenses when I was beginning with an SLR and interchangeable lenses. In looking through my manufacturer's catalog (Minolta) I did notice that most of the lenses in the common range had at least one model that accepted 55 mm diameter screw-in filters. On that basis, I selected my first "system." It ran; 28 mm, 35 mm, 58 mm, 100 mm, 200 mm, and 300 mm, all with a 55 mm diameter filter thread. Yes, in the longer focal lengths I had to accept the smaller aperture, but they were also cheaper. I chose to look at the whole system and tried for maximum compatibility and utilization of space in the carrying case. There is more than one way to approach the filter question.