Exemptions are authorized under certain conditions when it is impossible to avoid the use of RoHS substances for scientific and technical reasons. However, as science progresses, the intent is to get rid of these exemptions.
As a result, exemptions are revised by default every five years, per article 5 of Directive 2011/65/EU. Nevertheless, they can be modified at any time by the European Commission. Exemptions are either prolonged, modified, split, or set to expire. This is why it is crucial, as a manufacturer, to monitor the current exemptions and make sure your products still benefit from valid ones.