I am answering based on what i have heard and read in books.

A soul’s time in a particular body is fixed in terms of number of breaths at the time of birth based on one’s past karma.

Later if one lives in mode of goodness (saatvic) life the number of breaths used per day is less and his life can get extended.

Going to temple, doing homams etc form one part of saatvic life and so can help in extending one’s life as by good association and environment our rest of our day/life is also directed in saatvic direction.

In rare occasions , by God’s discretion , or by request of exalted devotees, Lord can change the number of breaths also. But usually HE gives us intelligence to use it wisely so that we can elongate the life for His service (which is actually our purification)

Hope it answers your question.