It is recommended that you change any pacifier/soother every 6-8 weeks for safety and hygiene reasons.
The soother/pacifier should be cleaned by hand or in a machine especially suitable for this, and must not be cleaned in a microwave or dishwasher. When the soother/pacifier is not in use, it should be kept in a clean, dry place out of direct sunlight or contact with a source of direct heat. It should be stored in a closed, clean and dry container. Check daily that the soother/pacifier is in good condition. This is done by pulling on the various parts of the soother and checking that it is still in good condition. If there are splits or changes in the soother, it should be discarded.