How can I create a subscription box where products are being changed each month?
Here is how you can create a subscription box with product swap functionality, where you cycle products with each renewal from product A to product B to product C and then back to product A.

You have to create these three product swaps:

Product swap #1:
- apply when subscription get created or renewed
- remove product A from the subscription
- add product B to the subscription

Product swap #2:
- apply when subscription get created or renewed
- remove product B from the subscription
- add product C to the subscription

Product swap #3:
- apply when subscription get created or renewed
- remove product C from the subscription
- add product A to the subscription

Here is a how it will work:
Customer buys product A as a subscription.
The system applies the swap and changes the product A to product B. Next renewal will contain product B.
You ship the product A from the initial order, as the initial order still contains product A.

Subscription gets renewed with product B.
The system applies swap and changes product B with product C. Next renewal will contain product C.
You ship the product B from the order that was created as a result of a subscription renewal.

Subscription gets renewed with product C.
The system applies swap and changes product C with product A. Next renewal will contain product A.
You ship the product C from the order that was created as a result of a subscription renewal.


We even have an option, which allows you to add a condition, where you remove product A and replace it with product B only if the subscription contains a specific product (e.g. product X, which represents the "subscription box").