I just limited my four month old daughters pacifier time. Now she has started using her thumb. What should I do ?

4mths old is still so young. it is difficult to let baby quit pacificer. for me personally i prefer pacificer than thumb. i feel thumb has more germs than pacificer. because at least i sterilised it after every use. but baby thumb i cant keep washing or clean with baby wipe. also it is easier to quit with pacificer. i thought it would be difficult. i tried 1day when my son is 18mths old. i didnt give him and just let him sleep as he is really tired that day. lights dimmed. he didnt ask for it and sleep through the night. so i tried the 2nd day and 3rd day and so on. he then totally forgot about it. now he is 4yrs old when he saw baby with pacificer, he cant rem that he ate that before. lol.