In the Periya Thirumozhi pasuram on Badarikashram, Thirumangai Azhvar sings thus (1-3-5):

paNdu kAmar AnavARum pAvaiyar vAyamudham
uNdavArum vAzhndhavArum okkavuraitthirumi
thaNdu kAlA oonRi oonRith thaLLi nadavA mun
vaNdu pAdum thaNthuzhAyAn vadhari vaNangudhumE

Here Azhvar, when describing an old man using a stick to stand himself up, uses the word 'oonRi' twice (oonRi oonRi). Azhvar is asking the people of this world to go to Badri before becoming an old man who needs a stick to stand and walk.

Pillai Azhagiya Manavala Araiyar showed Bhattar's explanation for the use of the word 'oonRi' twice instead of just once.

As a person gets really old, he loses the strength to even lean on the stick and stand steady. Therefore, he will keep lifting the stick up and plant it in the ground many times. This is why Azhvar repeats the word 'oonRi', explained Bhattar.