According to the spiritual science there are certain days that are beneficial for spiritual activities and multiplying their result. They are called Ekadasi. They are happening according to the lunar calendar at 11th day of waning and waxing moon. On these day it is recommended to fast from grains and beans and eat only vegan food + all kinds of milk products. This month it is 4th and 18th. And a very auspicious day that only happens once a year this time happens in March 22nd, day of the full moon. In some calendars this day is the beginning of a new year. On this day you can observe any type of fast including the full fast till moonrise.