I will discuss the behavior of distribution of residence times of grains in models of sandpiles and ricepiles. I show that in the models where the maximum numbers of grains per site remains fixed as the size of system is increased, the distribution scales as the mean mass of the pile, but the precise scaling function depends on the details of driving. In models where the critical threshold is on the slope, the long time tails are dominated by grains that get buried deep in the pile, and the probability density that time is T varies as T^{-2}, independent of the details of the model.

Tata Institute, Mumbai, India