A method for programming a memory block of a non-volatile memory structure, comprising determining whether a number of programming/erase cycles previously applied to the block exceeds a first programming/erase cycle threshold and, if the first threshold is exceeded, determining whether the number of programming/erase cycles previously applied to the block exceeds an extended programming/erase cycle threshold. Further, if the determination is made that the extended threshold is not exceeded, the method comprises applying a two-pulse per programming loop scheme to each of the outermost strings of the block and applying a single-pulse per programming loop scheme to all other strings of the block. Alternatively, or in addition thereto, relative to a programming/erase cycle threshold, one or more outermost strings of the block may be unpermitted to be further programmed, and a “sub-block” comprised of all valid strings of the block may be defined and permitted for further programming.