The Krishna Paksha Chaturthi of every month is called by the name (Sankastha Chaturthi).
The word Puja is derived: Puh means "the achievement of the fruits of enjoyments". The daily and occasional rites yield their benefits in due course but the fruits of Kamya rites are instant. The necessary rites are performed every day.
The occasional rites are performed in particularly months, fortnights, years on special occasions.
In the Kamya rites one derives the fruits after sin has been stop. Mahaganapati Puja shall be performed on the 4th day of the Krishna Paksha of the Lunar month. This rite removes of the sins of the whole fortnight and gives enjoyment for full fortnight.
The worship performed on the 4th day of the Lunar month Chaitra gives benefits for a month. The worship performed in the months of Simha (Leo) and Bhadrapad gives enjoyment of the worldly pleasure for a year.
The days of special worship of Ganesh are Fridays, the 4th day of the bright half of the Lunar months of Sravana and Bhadrapad and Satabisha star of the month of Sagittarius. He shall be worshiped duly on these days. The person shall worship continuously for 100 or 1000 days. While North Indians are believers of Vishnu and South Indians believe in Shiva, Ganesh is worshipped throughout India.