A system and methodology for human behavior modification or maintenance implemented by electronic two way communication between a host computing device with software adapted to the task, and a user. The system employs collected data regarding user identity, availability, and behavior, and generates a customized program of sequential events during identified user available time segments on a plurality of days. The events are constantly re-allotted to the available time in given daily time segments through a feedback acknowledgment from the user subsequent to communications sent to the user about an event. This results in a constantly updated program based on user responses which continually adjusts for the remaining time in the time segment on any day during the program. The program is customizable by user input requests such as exclusion of time during the daily time segments, front loading or rear loading of daily events, program day extensions or reductions, starting a program day earlier than the regularly scheduled time, inserting plateaus to repeat days in a program, and backsetting or forwardsetting within a program profile. A shaping function may be employed to further customize the program.