Pacifiers usually last around 2 months but always check the pacifier for any tears or signs that the pacifier is coming apart.
Discard the pacifier if it has any signs of tears etc as it can be a choking hazard to your baby.
Pacifiers are good for soothing your baby and preventing SIDS but always check the pacifier to be sure it's in a safe condition.
If in doubt throw it out and get your child a new pacifier as it's not worth the choking risk.