Do I need to prove my age every time I place an order?

If you have created an account with you will only need to complete the process once. When your account has been age confirmed you will be able to log in and make purchases without needing to age confirm again.
If you are not logged into your account, or prefer to use guest checkout, you will need to complete the age confirmation in 'Step 3' of the checkout process. But please note, if you checkout as a guest, your age conformation is not saved against an account and will need to be completed every time you choose to checkout.