This policy change could allow the price of your app subscriptions to double in just two years.

If you're an Apple customer and have an app subscription on your iPhone, iPad or Mac, your app could charge you more without your consent. Apple updated its App Store policy Monday and now allows some apps to charge more for auto-renewable subscriptions without requiring customers to take any action. However, there are some conditions to the policy update.

"The specific conditions for this feature are that the price increase doesn't occur more than once per year, doesn't exceed US $5 and 50% of the subscription price, or US $50 and 50% for an annual subscription price, and is permissible by local law," Apple wrote.

This means a developer can't incrementally raise the price of a subscription two or three times in a year. It also means if you subscribe to a service and the monthly fee is $10, the subscription can increase to $15 a month without asking you to opt in. Over a year, the cost of that subscription would inflate from $120 to $180.

If a price increase violates either the $5 or 50% conditions, Apple said, customers will have to opt into the price changes. If the increase is too high, Apple said it will let customers know how to view, manage and cancel subscriptions. Customers can also request a refund or report issues through Settings under Purchase History, on Apple's website or in the App Store.

Apple said its current policy requires developers to message customers, asking them to opt into price increases before the increase is applied. Some customers would miss these messages, according to Apple, causing the service to be interrupted and for those customers to have to go through the signup process again. The new policy seems to be designed to prevent unintended interruptions.

But while this new policy might be more convenient for some customers, it also makes it easier for apps to increase prices without the need for subscribers to do anything. Apple said it will send customers messages about price increases in advance by email, push notification or in-app messages. However, the new message is meant to notify customers, rather than call on them to act. If the price increase falls within the $5 and 50% parameters, it will happen automatically unless you cancel or otherwise change your subscription.

The policy places a bigger burden on customers to monitor their subscriptions. If a subscription costs $10 per month, it could rise to $25 per month in three years. That's an extra $180 per year. Now imagine you have two other apps that follow the same price increase. You're now paying $75 per month for three apps that cost a fraction of that years prior.

With this new policy, you will now have to be more vigilant about price increases and what subscriptions to keep and which to delete.