Once, before a great cataclysm, there was a sect of elves from a floating continent who could summon ethereal wings to their back. Now, with magic fractured and uncertain, they only have a short time that they can summon their wings before they need to recharge their magic. How do they train their young to be careful with this gift?
Ideas and questions:
Perhaps the elves within your story have anecdotal stories to share with their younglings about how misuse of their power caused great tragedy.
The elves may have different ways of determining when too much of their magic use is enough. They could limit themselves to a few minutes and then a wait, or they could assign themselves a certain duration that they can fly each day.
Do the elves of your story train their youths on how to use their summoned wings prior to their appearance, or do they wait until the gift manifests?
Are the elves you are writing about afraid to use their power, or do they find it to be a great utility that they use frequently?
Do the adults know exactly how much time they have available to them, or is there a threshold to the amount of time they allow themselves. How have they tested this?
Write your story within the context of a parent who has already lost one child who misused their talent. Perhaps you can write about the psychological impact it has on the various characters.