Q. Thank you so much for answering my previous questions, I have a few more.
I was in shul and someone borrowed a hundred dollars so he could pay for his overdue aliyos. I understood that he would repay it a.s.a.p. the next day. When I asked him then for the money he said he has 30 days to repay, is that correct?

A. Shulchan Aruch (C.M. 73: 1) rules that only when there is no established custom the rule of thirty days for repayment applies, otherwise whatever the common local practice is will take effect. Ritvo (Makos 3b) maintains that it is not the way of people to borrow money and repay it immediately or the next day, but that may not be true for small amounts. Mishna Berura (307: 42) quotes Magen Avrohom (ibid.) that in his location money loans were collected immediately.

Horav Shlomo Miller’s Shlit”a opinion is that when in doubt as to what the local tradition is, the thirty day rule will apply.

Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit”a