Mudgalapurana 3.19.6

3.19.6

caturthīvratamādyaṃ ca kartavyaṃ tvāśramasthitaiḥ |
tathā'nyāni vratādīni kartavyāni viśeṣataḥ ||

And the observance of the Fourth is foremost and must be performed by those in the stages of life; / so too other observances and the like should be performed especially.