Q: What is the role of minhag hamedinah (common commercial practice) in halachah?
A: Regarding sechirus po’alim (employment), the Mishnah (B.M. 83a) explicitly teaches that hakol k’minhag hamedinah (everything is in accordance with the common commercial practice). This relates to terms of employment, hours, wages, etc., when not specified in the contract (C.M. 331:2).
Talmud Yerushalmi (B.M. 7:1) comments on this, minhag mevatel halachah (when doubt or conflict arises, the common commercial practice supersedes the default halachah that applies in the absence of a common practice). This is because presumably the parties contracted in accordance with the minhag (see Chazon Ish B.B. 5:5).
Chasam Sofer (C.M. #12) maintains that the power of minhag hamedinah is d’oraysa.
In the coming series, b’ezras Hashem, we will address the laws of minhag hamedinah, some of its applications, and its parameters.
There is a distinction between a practice established by a formal agreement of the townspeople and one that evolved on its own from their behavior, as will be explained.
