What are the differences between Yagya and Puja / Homa ?
In Puja and Homa you have no restrictions. These are basically purposeless and just for devotion. A result is normally not expected after these Puja and Homa. The most important is that the mantras chanted in a puja is like 1 time or 10 times or 108 times or 1008 times while in Yagya the quantity is 25000, 51000, 125000. Naturally the Puja and Homa (hawans)] are done by one pandit in 1-3 hours while a Yagya with 125000 chanting takes 5 to 31 days depending upon the number of pandits like 3 or 5 or 7 or 9 or 11. A result of Yagya is normally expected. For a puja or Homa, the pandits in India are normally paid from Eur 5 to Eur 20/ or equivalent while the cost of Yagya goes much higher in that ratio and therefore not everyone can afford Yagya very often.
