For me, it's when I continue to meditate long after the guided meditation has ended. Once I see that I can use the techniques in the guided meditation after it's over, I apply them later on without the guided meditation
I've never gotten to the point where I could, due to lack of consistency. I'm easily distracted and have got a busy brain, it's hard for me to focus.
I would say, even if not doing a guided meditation, use a timer, so you don’t fall asleep or overthink when to stop meditating. Try to give yourself a minute to get comfy.
I don't feel ready to meditate without guidance, I'll be ready to start when I feel confident with the training I do for myself