If a dish usually takes:
15 - 30 mins, cook it for 1 - 2 hours on High or 4 - 6 hours on Low
30 mins - 1 hour, cook it for 2 - 3 hours on High or 5 - 7 hours on Low
1 - 2 hours, cook it for 3 - 4 hours on High or 6 - 8 hours on Low
2 - 4 hours, cook it for 4 - 6 hours on High or 8 - 12 hours...