Building big things through small manageable changes is a worthwhile method. With regard to programming I call it incremental twiddling. Take something that works, make a small (reversible) change, make sure it still works the way you expect it to, change some more, repeat. This method is akin to only changing one variable at a time, or as like to call it turning one knob at a time.
Incremental Twiddling
May 6, 2009