Reinventing the wheel is bad not only because it wastes time, but because reinvented wheels are often square. There is an almost irresistible temptation to economize on reinvention time by taking a shortcut to a crude and poorly-thought-out version, which in the long run often turns out to be false economy.

Henry Spencer (b. 1955) Canadian computer scientist, space enthusiast

(Attributed)

Quoted in E. Raymond, The Art of UNIX Programming, ch. 16 (2004)