Better Days?

In AN's life this far, there had been 2 periods where I am only looking forward to better days: her between 18-24 months, and her at 4 years old.

Then, she would want things but wasn't able to verbalise. Now, she wants things and will not take no for an answer.

She gets apologetic when she realises being THAT stubborn turns me off. I try not to dwell on an issue after she apologises but it seems she's taking that for granted and increasingly refuses to listen, because she can always say sorry and get away with it after that.

What's the right thing to do? Get a cane? Lock her outside the house?