WHETHER BY PERFORMING GAYA SRADDHAM , THE PERFORMANCE OF PRATYABDIKA SRADDHAM AND MAHALAYA TARPANAM CAN BE GIVEN UP?

Performing GayA SrAddham does not mean that one can give up the annual pratyAbdika SrAddham.
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As per Scriptures, the following are the three important duties of a Son:

1. Following the words of Parents when they are alive
2. Performance of annual ceremony (SrAddha)
3. Performance of pinda dAnam at GayA

jIvator vAkya karaNat pratyabdam bhUri bhojanAt !
gayAYAm piNda dAnAt ca tribhih putrasya putratA !!


Regarding MahAlaya tarpaNam , it is part of the shaNNavati (96) tarpaNams and hence has to be performed. There are two options given. First, it can be performed for 16 days (paksha mahAlayam) or it can be on a single day (sakrin mahAlayam). The second one is suggested in case one cannot perform it for 16 days.

GayA SrAddham is very important. It immensely pleases the Pitrus.But saying that after performing GayA SrAddham everything else need not be done is incorrect reading of the Scriptures.