My DD has just turned 4. She has sucked her thumb since birth. I am conscious I want it to come to an end due to damage to the roof of her mouth etc. I have spoken to her about it and tried to discourage her. She doesn't care in the slightest and is completely addicted to it. In fact, it's become worse since I started coaxing her to take the thumb out. I have looked at the nail biting stuff that tastes bitter but she will probably just wash it off. I see there are thumb guards you can buy too but surely she will just take them off. Anyone successfully stopped thumb sucking at this age? Any tips?