Releasing Production order

Dear Experts,

Please confirm me when i should release the planned order to production order to our shop floor.

1. Is it when all the materials are in stock ?

2. Is it by checking by RM delivering date coming from PO. I.e., if suppose my all RM delivery date are coming as 2.12.11 then today should i release the planned order to production order for date 3.12.11 for our shop floor.

3. Or other is any ?

Regards,