Non nutritive sucking is a normal way for babies to self sooth. They generally find less of a need to do this by age 2-3. If they are still steadfast on this habit beyond that age, pacifier use is better than thumb sucking, as it is an easier behavior to control. Try to reduce this habit by age 5-6 at the latest, because this is when the adult teeth start to come in, and this is when pacifier use can have the greatest effects on dental development and jaw growth.
If you are having difficulty getting your child to give up their pacifier, it may be helpful to try gradually reducing the amount of time they use it, or offering alternative comfort items like a stuffed animal or blanket. You can also try distracting them with other activities or offering positive reinforcement for not using the pacifier. It can be helpful to involve the child in the process and explain that they are growing up and don't need the pacifier anymore.