BG Chap 18 - Difference between sannyāsa and tyāga according to the learned

The learned know that sannyāsa means to give up all activities based on material desire (kāmya karma), such as putreṣṭi (sacrifices for gaining sons) and jyotiṣṭoma (for going to heavenly planets).This implies that one should not give up nitya-karma (daily obligatory activities) such as daily fire sacrifice and sandhya worship. Tyāga means to renounce the results of all activities – daily obligatory (nitya-karma) and out of personal desire (kāmya-karma) rather than giving up the activities themselves. One of the results of nitya-karma is to go to Pitṛloka. Thus sannyāsa means to give up kāmya-karmas completely, and to give up the results of nitya-karmas. Tyāga means to perform all actions, but to give up the desire for results of all those activities.