2.3 When to Enroll in the Apple Developer Program?
Clearly, there are many benefits to Apple Developer Program membership and, eventually, membership will be necessary to begin selling your apps. As to whether to pay the enrollment fee now or later will depend on individual circumstances. If you are still in the early stages of learning to develop iOS apps or have yet to come up with a compelling idea for an app to develop then much of what you need is provided without program membership. As your skill level increases and your ideas for apps to develop take shape you can, after all, always enroll in the developer program later.
If, on the other hand, you are confident that you will reach the stage of having an application ready to publish, or know that you will need access to more advanced features such as Siri support, iCloud storage, In-App Purchasing and Apple Pay then it is worth joining the developer program sooner rather than later.