Specific, definite, concrete Prefer the specific to the general, the definite to the vague, the concrete to the abstract. William Strunk Jr. & E.B. White, The Elements of Style examples
The requirements of economy Economy is the mother of most inventions, not necessity, unless in the sense of poverty and hardship. A requirement for convenience is simply a diluted requirement for ease and economy. It seems to be invariably true that those characteristics which lead people to call a design functional are derived from the requirements of economy and not of use. David Pye, The Nature and Aesthetics of Design Form follows functionEconomy of material and labor function