Thumb-sucking Quandary

The Girl has sucked her thumb since she was two weeks old. Self-soothing came very naturally for her. It still does.

I have told her that if she quits sucking her thumb we can paint her nails a sparkly pink. You know how she feels about pink sparkles. It hasn't worked.


What do you suggest? Let her be...she will outgrow it. Or should we take a more active approach? What's worked for you?