The decision, moved uphill
Summit decisions happen under fatigue, sunk cost, summit fever, and thin air — the worst possible committee. The turnaround moves that decision to the trailhead, where coffee, dry socks, and clear thinking reside. Every mountaineering curriculum teaches it; every SAR report is a story about skipping it.
Setting it properly
Half the moving time, plus half the safety buffer, measured from the START clock (not the route's midpoint, not "when we get to the ridge"). Write it down, set the watch alarm, and pre-agree it in groups — the pre-agreement is what removes the summit negotiation that sinks parties.
Honoring it when it hurts
The test arrives 15 minutes below the top, weather holding, everyone feeling great. The discipline holds because the time was not arbitrary: it priced the descent, the buffer, and the daylight. The summit is optional and permanent; the trailhead is mandatory and closer. Turn around — the mountain will be there, and so will the story of the time you turned around like a professional.