airplane rule n.
"Complexity increases the possibility of failure; a
twin-engine airplane has twice as many engine problems as a
single-engine airplane." By analogy, in both software and
electronics, the rule that simplicity increases robustness. It is
correspondingly argued that the right way to build reliable
systems is to put all your eggs in one basket, after making sure
that you've built a really good basket. See also KISS Principle, elegant.