Continuously or repeatedly over many months; doing something regularly month after month for an extended period.
Examples:
EN: You never really, really know until you've sat in it for 40 hours a week, for a month, month in, month out.
ES: No sabrás nunca, nunca realmente como es hasta que no te hayas sentado durante 40 horas a la semana en un mes... Mes tras mes. Y entonces será muy tarde.
EN: To me, it was a lot of fun to see that because it explores the world of these characters and it doesn't just give you one flavor month in, month out.
ES: Me encantó ver aquello porque ahonda en el mundo de esos personajes y no solo te da una perspectiva y punto.
EN: And just stayed there, month in, month out.
ES: Yasíquedéallí,enel mes,mesfuera.
EN: You been puttin' down two, three scores a month... month in, month out.
ES: Has estado anotando dos, tres puntajes al mes... mes tras mes.