When the buyer is willing to buy you at reasonable terms. The most critical element of this is the motivation of the buyer, and that is out of your control. The “open to buy” window is created when their strategy shows a need they need to address and do it yourself doesn’t really cut it. That’s when they start looking, and you need to make sure you show in their radar screen when they do. And that is the part which you CAN control. Sometimes this happens earlier than you would have liked, sometimes later. Timing is not in your hands. Accept it, and act accordingly.