प्रथमे नार्जिता विद्या द्वितीये नार्जितं धनम्।
तृतीये नार्जितं पुण्यं चतुर्थे किं करिष्यति॥
prathame nārjitā vidyā dvitīye nārjitaṁ dhanam|
tṛtīye nārjitaṁ puṇyaṁ caturthe kiṁ kariṣyati||
[One who has] not accumulated knowledge in his first [āshrama, i.e. brahmacharyam], [one who has] not accumulated wealth in his second [āshrama, i.e. gārhastyam];
[One who has not] accumulated good meritorious deeds (punya) in his third [āshrama, i.e. vānaprastham], what will he do in his fourth [āshrama, i.e. sanyāsam]?
I understand vānaprastha is not supposed to be followed in kaliyuga, so we can look at it as an extension of the gṛhastāshrama, where one must concentrate more on pilgrimage and slow detachment, rather than a full-fledged family life.