Bhagavad Gita
6.41

प्राप्य पुण्यकृतां लोकानुषित्वा शाश्वतीः समाः । शुचीनां श्रीमतां गेहे योगभ्रष्टोऽभिजायते ॥

prāpya puṇyakṛtāṃ lokānuṣitvā śāśvatīḥ samāḥ | śucīnāṃ śrīmatāṃ gehe yogabhraṣṭo'bhijāyate ||

Translation

Having reached the worlds of those who have performed meritorious deeds, and having dwelt there for immeasurable years, the fallen yogi is reborn in the home of the pure and prosperous.

Interpretation

Krishna describes the journey of the fallen yogi: they attain the higher worlds (punya-kritam lokan — the realms of those who have done good) and enjoy the fruits of their spiritual merit for vast stretches of time. Then they return to human birth — but not in any random family. They are reborn into homes that are shuchi (pure, spiritually inclined) and shrimat (prosperous, offering good conditions for practice). The spiritual merit does not evaporate; it provides the conditions for the practice to continue.