Quality
Krishna says that my devotee is never to be vanquished. And He behaves according to the quality or degree of the devotional service rendered.
Expertise
For coming to satoguna, take satvic Prasadam and rise up early.
Purpose
Service is for becoming free from Kama, krodha, lobha, moha, mada, matsarya and desire for name, fame, recognition.
No Exhaustion
Spiritual life means more you do, more you feel like doing. But material life means more you do, a point comes, you feel boring.