In Parasha haHodesh (Shemot /Exodus 12:1-20) that we read this week – we find “This shall be head of month…”. Hodesh is month in Hebrew. It can also be read Hadash – NEW.
Every month we have a chance to Renew ourselves and our commitment to Hashem and mitzvot. Each month [& day] G.d gives us a new opportunity for self improvement. Thus some do Yom Kippur Katan / Mini-Yom Kippur Erev Rosh Hodesh / Beginning of Hebrew Month.