The death anniversary of ancestors, also known as Srardham is performed every year in remembrance of the ancestors. It is performed on their death date (thithi).
By performing this srardham ritual with dedication and devotion, one can get ancestor blessings, which will lead to a very happy and prosperous life. To stress on the importance of performing ancestor rituals, on the eve of ancestor rituals like Tharpanam, Srardham…etc, daily worship of Gods should be done only after the rituals are performed. Hindu customs and beliefs have attached such a great importance to them.