When mottling begins how soon will death occur?

In my experience 4 hours is average. Some nurses say 10 is average. Once I see mottling, I immediately notify family I do not expect my patient to live through the day. I have only seen one case where the patient lived longer than one day, she lived 3 days and all the nurses were surprised to see the mottling progress all the way to her neck before she died. I rarely see it progress past knees and elbows. Mottling is one sure sign of death, but it does not give a precise and definitive timeline.