It’s a milestone approach, releasing funds at significant life stages, Jeffrey explains. “Maybe a third of the amount at age 30, a third at 35 and the final third at 40. But you don’t want to constrain it to specific actions,” says Jeffery. “You hope they get it right, but if they make some poor investments, they have two more thirds still to come.”
Source: https://support.google.com/assistant/thread/306194038?hl=en&sjid=10664347457836306421-AP