Feminized seeds do not lose their feminized status with age, but very old seeds that struggle to germinate can produce weaker seedlings more prone to stress. Vendors sometimes hold stock for years without clear batch dating on the pack. Batch age reports on https://potentthcseeds.com (https://potentthcseeds.com) are submitted by buyers who received dated packaging, giving a rough idea of how fresh a vendor's stock tends to be. Asking a vendor directly about batch dates before ordering is reasonable and usually answered.