Custom fills gaps but must never contradict express contract terms

Evidence

It is the function of custom to fill in the interstices of an agreement, to reduce the burdiks of making written memoranda of agreement, and to substitute for agreement with respect to matters overlooked or not expressly foreseen. It is not the function of custom to contradict the terms of an agreement. … Respect by lawyers and judges for strict performance and for custom is basic to respect for the law by laymen. The two concepts - strict performance of agreements, and interpretation of agreements by resort to custom and usage - are entirely consistent, But each, in relation to the other, must be confined to its proper area. — Henry M. Hart, Jr. and Albert M. Sacks, The Legal Process, 888

Categorization

• DEFINE: Distinguishes custom’s interstitial function from impermissible contradiction of agreement terms.
• XREF: connects to: Trust extends beyond what written contracts can enforce — Diego Gambetta, Trust - Making and Breaking Cooperative…, 801

Broader Connections

• Trust extends beyond what written contracts can enforce #complicates (0.75) — Diego Gambetta, Trust - Making and Breaking Cooperative…, 801