Can be sudden; can be gradual. Don’t “wait,” nor “expect,” nor “name,” nor “touch.” It’s already here. You just don’t see that part yet. Really, only don’t know. That’s how you go. One day, something “new” emerges that has already always been so familiar. It’s sometimes described as waking up. Regular, consistent practice strengthens your connection to “it”, your stability in “it.“ Then the only real lifelong work that remains is integrating this wakefulness into the thicket of habit-formation which you have clung to for your whole life, possibly even for millennia. That is the only tricky part. Anyway, “sudden“ and then “gradual” have their meaning in this.