סימן צד סעיף יא
יֵשׁ לַעֲשׂוֹת עֵרוּבֵי חֲצֵרוֹת בְּכָל עֶרֶב שַׁבָּת, וּבְשַׁבָּת יִבְצַע עָלָיו, כְּדִלְקַמָּן סִימָן ק"ב סָעִיף ב, (כִּי אֵינוֹ צָרִיךְ לִהְיוֹת קַיָּם רַק בִּכְנִסַת שַׁבָּת). אַךְ אִם יֵשׁ לָחוּשׁ פֶּן יִשְׁכַּח פַּעַם אַחַת, יָכוֹל לְעָרֵב בְּכִכָּר אֶחָד לְכָל הַשַׁבָּתוֹת שֶׁעַד הַפֶּסַח. וּכְשֶׁאוֹמֵר בַּהֲדֵין וְכוּ' יְסַיֵּם בְּכָל הַשַׁבָּתוֹת שֶׁעַד הַפֶּסַח הַבָּא עָלֵינוּ לְטוֹבָה. וְצָרִיךְ שֶׁיַּעֲשֶׂה הַכִּכָּר, דַּק וְאָפוּי הֵיטֵב שֶׁלֹּא יִתְקַלְקֵל. וּלְשַׁבָּת שֶׁבְּתוֹךְ הַפֶּסַח, יַעֲשֶׂה הָעֵרוּב בְּמַצָּה כְּשֵׁרָה (שס"ח שצ"ג).
The eiruv should be made every erev Shabbos,32The Mishnah Berurah 368: 21 says that it is preferable to have an eiruv in the synagogue for everyone. Nevertheless, every person who needs an eiruv should make his own every week without a berachah and grant ownership to everyone in his court (in case the one in the synagogue becomes spoiled). and on Shabbos, Hamotzi should be said over it,33Maseches Shabbos 117b—since one mitzvah was done with it, it is fitting that another one be done with it. The Ariz’l said Hamotzi at night over the bread from the partnership of the alley (שִׁיתּוּף מְבוֹאוֹת) and in the morning on the loaf of eiruvei chatzeiros. [Sha’ar Hakavanos] [and it should be eaten], as stated in Chapter 102:2 below, (for it has to be on hand) only at the beginning of Shabbos). But if you are afraid that you might in the future forget [to make an eiruv], you may make an eiruv with one loaf of bread for all the Shabbosos until Pesach, and [in this case], when you say: "By means of this eiruv etc." you should conclude: "For all the Shabbosos until Pesach which will come to us for goodness." And [in this case] it is necessary that the loaf is thin and well baked, so that it will not become spoiled. For the Shabbos during Pesach you must make the eiruv with matzoh that is kosher for Pesach.
תנא דבי אליהו כל השונה הלכות בכל יום מובטח לו שהוא בן העולם הבא שנאמר הליכות עולם לו אל תקרי הליכות אלא הלכות (נדה ע"ג.)