After you place your initial subscription order, you will be billed immediately for your first box shipment or first batch of prepaid months (if you ordered a multi-month subscription). Your next renewal date will be on the same day of the month 1, 3, 6, or 12 months later depending on which plan you chose.
For example, if you order Seoul Deluxe Subscription (Billed Every 1 Month) on 5th December, your initial box is January Seoul Box and will ship out within 1 week, and you will be billed again on 5th January for your February Seoul Box shipment. If you order on 1st January, your initial box is February Seoul Box, so you won't be billed again until 1st February for your March Seoul Box shipment.
If you order Seoul Deluxe Subscription (Billed Every 3 Months) on 5th December, your initial box is January Seoul Box, and your next prepaid order will be submitted on 5th January. Since you chose to be billed every 3 months, you will next be billed on 5th March as you already prepaid for the 5th December, 5th January and 5th February renewals. If you order on 1st January, your initial box will be February Seoul Box, so you won't be billed again until 1st April for your next 3 prepaid months of boxes.