===Who is obligated?===
# A blind person isn't obligated to tear his clothing in mourning. <ref> Tzitz Eliezer 16:39, Rav Yechiel Michel Tucatzinski in Ir Hakodesh Vihamikdash 17:1 </ref># One is obligated to tear his garments if he visits on a Friday. <ref> Rav Schachter Bi'
ivei Hatzon 18 says that some people think that they wouldn't be obligated because the Rama YD 399:3 says that one doesn't mourn on erev pesach after mid-day. However, the Or Zarua Hilchot Aveilut 432 says this is only because of the korban pesach so this halacha wouldn't apply to a regular erev shabbat or erev yom tov. </ref>
# The practice nowadays is not to tear during Chol Hamoed. <ref> Rav Yechiel Michel Tukatzinski Ir HaKodesh V'HaMikdash 17:1 </ref>