An operation method of a storage controller which includes a nonvolatile memory device, the method including: collecting a first parameter indicating a degradation factor of a first memory area of the nonvolatile memory device and a second parameter indicating a degree of degradation occurring at the first memory area, in an initial driving period; selecting a first function model of a plurality of function models based on the first parameter and the second parameter and predicting a first error tendency of the first memory area based on the first function model; determining a first reliability interval based on the first error tendency; and performing a first reliability operation on the first memory area of the nonvolatile memory device based on the first reliability interval.