Flag designs exhibit a number of regularities, arising from a variety of practical concerns, historical circumstances, and cultural prescriptions that have shaped and continue to shape their evolution.

First among the practical issues confronting a vexillographer is the necessity for the design to be manufactured (and often mass produced) into or onto a piece of cloth, which will subsequently be hoisted aloft in the outdoors to represent an organization, individual, or idea. In this respect, flag design departs considerably from loo design: whereas logos are predominantly still images to be read off a page, screen, or billboard, flags are alternately draped and fluttering images to be seen from a variety of distances and angles. The prevalence of simple bold colors and shapes in flag design attests to these practical issues.

Flag design is also a historical process in which current designs often refer back to previous designs, effectively quoting, elaborating, or commenting upon them. Families of current flags may derive from a few common ancestors as in the cases of the Pan-African colors, the Pan-Arab colors, the Pan-Slavic colors, and the national flags inspired by the flag of Turkey.