The tipping point either way is often something so unexpected that you don't notice until you've passed it. Yellow leaves. A shut door. The fine silk of a tulip.
There is light in the mornings now as I head to the office. Even though the progression is the same, the return of light in spring seems to happen more quickly than the winter spread of dark. Perhaps the sun simply draws our gaze.
But I flew too close once and am lucky to have made it back. If you believe in luck.