The Challenge of Aging, Is It Enough?

As you're aging, everything's new, everything's a challenge. And then you hit the plateau where suddenly you could get very comfortable,. Where nothing's new and nothing's o challenge. Plenty of companies are trying to cash in on this as being a potential helper. What is the level of stimulus needed? Is doing te sdoku puzzle a couple of days a week enough? Ors it really need to be something continual everyday, multiple hours a day?