How to use Drupal Commerce subscription products? I created a site which has premium membership and want users to pay for those memberships.
I have installed commerce_sp on my site but I don't know how to configure it and use it.

When a member pay for a membership for 1 year, for example:
Subscription validity: 2014-09-25 13:45:00

but I don't know why, when I check this member again every once in a while. the Subscription validity has changed to: 2015-09-24 13:45:00. 

And I check this member again tomorrow,the Subscription validity has changed again:2017-09-22 13:45:00.

I don't know why the subscription validity change again and again.

I was very confused, anybody know why?
Most probably you have got issue with your rule set. Best way to use(configure) commerce_sp or even commerce product for membership is to put proper condition &amp; then fire the event.

Simple Config :


Create new products (using Subscription Products).
Create product displays for those products.
Go to Configuration>Rules.
Find the Rule called "Subscription Started (update)" and clone it.
Rename the cloned rule.
Make the Event "Completing the Checkout Process". Add some more like "user of type" etc.
Make the Elements "Order contains a particular product" and specify the SKUs of your subscription products.
For Actions, use "rule set: Subscription start" with parameter as "User:[commerce-order:owner] and "Schedule component evaluation" as is and added "Add user role" with Parameter: User:[commerce-order:owner] and Roles: my subscriber role.
Set the low weight for this rule set.


You can modify rule as per your requirement &amp; it will work accordingly.