Most of us want our children to have the best of everything, but not too much of anything.

As a result, some families with much more than average impose a form of enforced (yet totally artificial) deprivation. Frequently the “no” is not because they can’t afford it, but because the word “enough” is flashing on some scoreboard somewhere that only they can see.

Meanwhile, those of us who grew up hearing “no” a lot are tempted to say “yes” as much as we can, if we can possibly afford to. We want our kids to live better lives than we did as children — and better ones than we could afford last year.

Whether a family is affluent or struggling, however, every question about children and money and values eventually boils down to this: How much is enough? And how much is too much?

Consider one of the most recent objects of desire: The hoverboard. Before it became crystal-clear that its explosive battery was reason enough to ban it on safety grounds, parents struggled with the flashiness and the hefty price. To read more from RON LIEBER.