Under EU REACH there is no fixed calendar deadline for reviewing or re-issuing an SDS.  
Instead, fragrance chemicals suppliers must revise and provide a new, dated version without delay whenever any of the following occurs:

1. New hazard information (e.g. changed classification, new toxicological data).  
2. New risk-management measures (e.g. altered exposure controls or PPE).  
3. Authorisation granted or refused for the substance.  
4. A restriction is imposed under REACH.  
5. Registration-number or composition changes resulting from the REACH registration process .

Once an update is made, the fragrance chemicals suppliers must automatically send the latest SDS free of charge to every customer who received the substance or mixture in the preceding 12 months .

Best-practice recommendation for buyers:  
• Ask the supplier to confirm in writing every 12 months whether the SDS has been revised.  
• If you become aware of any regulatory or formulation change, request the new SDS immediately.