115. Errors within 30 Days
19:7 If someone made a mistake and said tal u’matar in the summer months, he must return to the start of the blessing “bareich aleinu.” If he didn’t remember until after saying the verse “yihiyu l’ratzon” at the end of Shemoneh Esrei, he must repeat the entire Shemoneh Esrei. 19:8 What if one can’t recall whether or not he said “mashiv haruach?” If it is after 30 days of saying the insertion, since he has already said the text properly 90 times, he can assume that he said it correctly. (More than 90, actually, since there is also musaf on Shabbos. Nevertheless, one must have completed 30 days and not 90 Shemoneh Esreis – Mishnah Brurah 114:37.) If it is within 30 days, he must repeat Shemoneh Esrei. The same is true for tal u’matar: after 30 days, one may assume that he said it correctly but before that, he must repeat Shemoneh Esrei. (Here, he said tal u’matar fewer than 90 times, since it is not said at all on Shabbos. As we said, the main issue is the 30 days, not the number of Shemoneh Esreis – MB 114:37 again.)