Unlimited.
You can purchase EPF fund at any time provided you have sufficient balance in your EPF account 1. The eligible amount will be valid for 3 months beginning from the attempted e-MIS transaction. EPF will refresh your new eligible investment amount after 3 months of your last EPF investment.
For example, if you attempt an e-MIS transaction on 4 January 2019, the validity period will count from 4 January 2019 to 3 April 2019. You can make unlimited transactions subject to your available balance in EPF account 1 within the validity period. After 3 months of your EPF order, EPF will refresh your new eligible amount and your new validity period for the new amount.