Answer:
A person's greatest asset.
Its days are numbered.
In birth I spring forth, in life I unfold. In death I wilt and die, but rebirth restores all.
If you blow past your destination, you'll have to throw your car into this.
It's in your hand though you cannot feel it. Only you and time can reveal it.
All about, but cannot be seen, Can be captured, cannot be held, No throat, but can be heard. Who am I?