Choosing the time
Texts give a usual age or day for each saṃskāra, and families often ask an astrologer or priest for a muhūrta — an auspicious date and time based on tithi, nakṣatra and other factors.
Tradition also allows flexibility: if the ideal time has passed, a rite can usually be done later. A convenient date when the family can gather is perfectly acceptable for most saṃskāras.