My son started to use dummy when he was 1 month old.
We used it to help him to sleep.
He also didnt use it much in day time.
I read some articles on the net that you dont have to stop babies using dummy unless they use it for a long time or you dont feed them but put a dummy in their mouths.
My son didnt need a dummy to sleep when he was 3 months.
We then tried not to give it to him.
We would cuddle him and rock him instead of giving him dummy.
It worked.
My midwife told me that if babies stop using dummy before 4 month, they will forget it completely.
My son doesnt use a dummy since then and he never cries for a dummy anymore.
Hope it help!!