A camera bag can become inefficient in ways that do not look dramatic at first. One of the easiest places this happens is filter management. A photographer buys a 67mm circular polarizer for one lens, then a 72mm variable ND for another, then maybe a 77mm protective filter for a third. Before long, the bag contains a small metal ecosystem of duplicate accessories, mismatched caps, extra cases, and a constant need to remember what fits what.