HALACHA OF THE WEEK: RECITING SHEHECHYANU DURING THE THREE WEEKS
For a review of the laws of the Three Weeks, Nine Day and 9 B'Av click here - https://www.congkins.org/three-weeks-landing-page.html
Because these weeks mark a period of intense mourning and tragedy, the custom is to refrain from reciting the bracha of shehechyanu - after all, how can we honestly say "shehechyanu... la'zeman hazeh" - that we are thrilled to once again enter this time of year!?
Therefore, from the 17th of Tammuz and until after the 9th of Av we generally refrain from wearing new clothing, eating a new fruit or buying new items that require a bracha of shehecheyanu [Shulchan Aruch 551:17; Mishna Berura ibid., note 99].
However, many poskim opine that one may recite the bracha of shehecheyanu on Shabbat until Rosh Chodosh [Aruch HaShulchan 551:38; Mishna Berura ibid., note 98]. Therefore, if the new fruit can last until Shabbat, one should wait until Shabbat, otherwise it may be recited during the week [Mishna Berura ibid. note 101] The same is true for new clothes, and especially if there is a special occasion such as a bar mitzvah or bris [Yechave Daat 1:37]. However, there are those who are stringent and permit this only about a fruit which is seasonal but not regarding other items such as clothing [Chayei Adam 14].
Clothing that does not require a bracha of shehecheyanu may be purchased until Rosh Chodosh, therefore, one may purchase socks, shirt, shoes, ties, dishes or any other item [Mishna Berura, ibid. note 45]. If there is a big sale than one may purchase the garment although they require that one recite a shehecheyanu, however, it may not be worn until after Tisha B'Av [Mishna Berura ibid., note 11; Shaar Hatziyun note 12; Kaf HaChaim note 12].
One should refrain from buying a house during the three weeks unless one is in desperate need [Rivovot Efraim 2:155 and 3:341; Nitai Gavriel 7;9]. Similarly, one should not move into a new house during the three weeks. If one cannot wait, then one should put up mezuzot and take some of belongings into the apt or house before the seventeenth of Tammuz [Levush Mordechai 1:101].