Do people typically order Niputz Lishma?
From our sales reports most people do not buy niputz – but that certainly should not sway your decision – niputz is a humra of having the lishma aspect start one step sooner in the process. As you may be aware, the Shulhan Aruch (OH 11:1) states that one must have tevia (spinning) lishma and the Rama notes that some are “machmirin” to have niputz lishma, though he says the custom is to be lenient. The Mishna Berura (OH 11:3) explains that the mitzvah of making tzitzit “taaseh lecha gedilim” starts with the tevia, however, he notes that the Prisha states in the name of the Maharal of Prague that l’chathila one should be strict and use niputz lishma. The Aruch HaShulhan (OH 11:4) explains the Maharal’s reasoning is that “taaseh lecha gedilim” is stated in conjunction with shatnez, and the making of shatnez includes the act of niputz, so one needs lishma at this level of the process. The Aruch Hashulhan thus concludes that one should be “careful with this.”
– Mois Navon.