100% permanence isn’t possible. You’re always being programmed by something – if it isn’t a subliminal of your choosing, it’s society. The human mind is a dynamic, ever changing system. There’s no way to force it to be completely static, and you wouldn’t want that anyway. The things you desire now won’t be the things you desire in 10 years. Change is good.
That being said, the lessons you learn when running a sub, and much of the scripting will always remain with you in some form or fashion. The things I learned while running the sub I created to develop Zero Point still remain with me, but it’s not as prominent as before. Those who run Zero Point for the first time often reports a feeling of connectedness with the self and the universe that feels uncanny (what we call the Zero Point Perspective Shift), but that stops occurring eventually as you become acclimated to the lessons.
In order for a sub to be a tool of growth and not a “programming tool,” 100% permanence can never be possible.
That’s the long answer. The short answer: 3 cycles of a sub should get you quite far.