How often should we change the Vilakku Thiri?

All things submitted to God once - like flowers, fruits, deepam and karpooram all attain the status of "Nirmaalyam" - meaning it is already used up, and cannot be used again for worship.

Deepam, which is lit once, also belongs to this category - the wick (thiri) which is used as part of the deepam also falls under this. As per Dharma Sastra, you should not reuse a wick if it has already been used for lighting and a part of it is burnt out in the process, since it has already become a nirmaalyam.

Hence, while lighting deepam in the sanctum sanctorum of God either at residences or temples or during any auspicious occasions, it would be best to use brand new wicks made out of pure cotton, instead of lighting them using partially burnt out wicks. That would ensure the receipt of complete benefits.

Above information is shared by Brahmasree Nannilam Rajagopala Ganapatigal, in his magazine Vaidhikasri (August 2012 issue).

Pranams.

Thank you for the excellent answer.

I will follow in changing the wick daily.

Jaya Jaya Sankara Hara Hara Sankara.

can we allow continues burning of vilaku?( without putting off the fire) only on thursday while changing the vilaku can we lit it afresh?