FIRST: You wrote a nifty program.

THEN: You sold it 50 times, customizing it each time.

NOW: You've fixed a bug in the standard version, and you must migrate the fix into each of the customized versions. In fact, you fix bugs or make other improvements every week, and you must get all those improvements to each of your 50 customers, at least monthly.

TLIB's Named Project Levels and Whole-level Change Migration make it possible (almost easy!) to add all your changes to any customized version, as often as you like.

Whole-level Change Migration: if you need it, you really need it. Only TLIB Version Control has it!