I think more in terms of edge length than total blade length, and blade shape impacts how useful the entire length of the edge may be. Also the handle/grip area needs to be sufficient, and while handle length may generally correlate to blade length, they're not directly related. In addition, "pocketability" depends on more than just handle length: like handle thickness and shape, clip design, and scale surface. My decision on which knife to carry often comes down to prioritizing pocketability vs. edge length.
But the original question was regarding blade size. I like having a 3-inch edge length, but even the 2.35-inch edge of the Chaparral usually works for my EDC needs. Plus its grip area (handle plus choil) is comfortable, and it disappears in the pocket. For me, EDC blade edge length varies between that of the Chaparral and the 3.3-inch length of the Spydiechef.
However, at work I sometimes limit the length to 2.5 inches due to a general university rule that sets that restriction. It doesn't apply when I carry the knife for work purposes, which I do, but if I want not to worry about being confronted on that matter and needing to justify the added length, I'll carry a small knife.