According to Osho, once the fourth stage flowers, the issue is self-evident: practice continues only if needed; otherwise the earlier stages fall away on their own. But he won’t promise this in advance, because the mind uses such promises to avoid the first three stages, which are essential to dissolve fear and repression. Enter them totally, let spontaneity happen; after the fourth, what remains or drops will reveal itself.
Don’t worry now about whether steps 1–3 will vanish; do them fully to clear fears, and when step 4 happens you’ll naturally know what to keep or drop.