Even if your yearly purchases stay the same, some companies offer a volume discount and free delivery as soon as your order exceeds a specific threshold.
However, success with customer subscriptions requires excellent inventory management. Customers will likely cancel their subscriptions when they experience that a seller is often out of the items they have subscribed to.
Good tips, I would like to set up subscriptions on my shopify store
Here is a Shopify article about how to set up subscriptions on Shopify:
https://help.shopify.com/en/manual/products/purchase-options/subscriptions/setup
However, success with customer subscriptions requires excellent inventory management. Customers will likely cancel their subscriptions when they experience that a seller is often out of the items they have subscribed to.