One of my favorite college professors talked a lot about "the tipping point," especially for social changes. Things build and build until finally, something pushes us over the edge into action. Think of the civil rights and equality/freedom movements around the world. People put up with things for so long and then wham! suddenly they're fighting back. Somewhere else I heard this saying, "Day to day nothing changes, then all of a sudden, everything is different."
I'm at a tipping point with exhaustion. I'm just waiting for our trip to pass and for Raccoon's last molar to put in an appearance before I try to tease out what is behavioral and needs some serious attention vs what is a sensory issue and needs to be addressed with therapy.