在继续之前，请参阅此链接帖子的评论，说明为什么使用自动续订订阅可能不是一个坏主意。

Before I proceed, please see the comments on this linked post on why it may be a bad idea to use auto-renewing subscriptions.

如果你之前听过这个话，请阻止我。

当你选择自动续订订阅时在iTunes Connect中，您有机会添加多个持续时间，并将不同的产品ID添加到一个订阅 Family 。 Apple不允许用户在一个系列中购买多个重叠的订阅持续时间。 （如果您在应用中使用多个系列，请说明推理，因此我可以根据该提示为您提供指导）。

Stop me if you've heard this before.
When you choose Auto-Renewable Subscriptions in iTunes Connect, you are given the opportunity to add multiple durations, with different Product ID's to one subscription Family. Apple won't allow a user to purchase multiple, overlapping subscription durations within one family. (If you're using multiple families in your app, please explain the reasoning, so I can give you guidance based on that).

事实上，Apple不会让用户在一个家庭中堆叠不同的订阅持续时间。

In fact, Apple won't let the user stack different durations of a subscription within one family.

以下是一个示例。

我（作为用户）下载假设的Acme应用并订阅1个月的订阅。如果我什么都不做，我的订阅将在期末自动续订另外一个月的订阅。等等。

Here's an example.
I (as a user) download the hypothetical Acme app and subscribe with a 1-month subscription. If I do nothing, my subscription will automatically renew at the end of the period with another 1-month subscription. And so on.

但我又回去购买了6个月的订阅。 Apple会告诉我（提醒）我的6个月订阅将在我目前的1个月订阅完成后开始，我想继续。如果我说是的话，Apple会记录下来，但是在我目前的1个月结束之前他们不会向我收费。

But instead I go back in and purchase a 6-month subscription. Apple will tell me (with an alert) that my 6-month subscription will begin at the completion of my current 1-month subscription, and would I like to proceed. If I say yes, Apple will make note of it, but they won't charge me until my current 1-month is up.

现在如果我再次回来并购买一年的订阅，然后Apple会再次发出警告，告诉我它将在我当前的1个月订阅结束时开始。它将不会添加到即将到来的6个月订阅中。它将取代它。

Now if I go back in again and purchase a 1-year subscription, then again Apple would respond with an alert telling me that it will begin at the end of my current 1-month subscription. It won't get added to the upcoming 6-month subscription. It will replace it.

摘要

因此，用户只能拥有一个当前订阅和一个即将进入的订阅（在系列中。这就是您在订阅中使用一系列产品持续时间的原因。如果您创建多个订阅系列，那么它们可以同时存在，并且您将失去该保护。

In Summary
So a user can only have one Current subscription and one Upcoming subscription (within a family. This is why you use a Family of product durations within a subscription. If you create multiple subscription families then they can exist simultaneously, and you loose that protection.

如果作为开发人员，您希望手动扩展，缩短，取消或堆叠订阅，那么您应该使用不续订订阅。如果您阅读我发布在顶部的链接，你会发现苹果可能会迫使你这样做。

If, as a developer, you'd like to manually extend, shorten, cancel or stack subscriptions, you should be doing it with Non-Renewing Subscriptions. And if you read the link I posted at the top, you'll realize that Apple may force you to do that.