Typically, something will become harder for her, let's say some aspect of getting dressed. If you follow your natural inclination and help her, she will let you. I won't say that she's happy to let you because, initially, she still feels that she should be able to do it herself. But as time passes, you do it more and more and she does it less and less though still, on occasions, will be able to do it without help. Over time though, what started as hard becomes very difficult and then impossible. One more skill is lost.
Now, I try much harder to resist the temptation to help when I think that she might just be able to do it herself. But still I often intervene as she is finding it so frustrating.
There's no point in dwelling on these things - you can only do what you can do - but if I was starting again I would try much harder to preserve her independence at all cost.