When and why did we stop wearing sackcloth in times of mourning and other times of distress (e.g., when fasting for rain)? (I presume sackcloth was quite uncomfortable.) Sackcloth is mentioned in the Torah in Bereshis 37:34 (Yaakov put on sackcloth after getting Joseph's coat of many colors dipped in blood), and is also mentioned in a couple of dozen places in various other Books of the Bible.
(Since writing this, I've heard that in recent past (in memory of the living) when fasts were called in Israel, at least some wore sackcloth.)