title: Automatically delete items from subscriptions database after they have expired?
body: <p>I am creating a website were user can subscribe packages for one month (Pretty much the same as newsletter subscription 5$/month).  how can i manage these subscription packages. whether i need to delete the item permanently after the expiration date? what is the best method.</p>
  
  <h3>models.py</h3>
  
  <pre><code>class avail_packs(models.Model):
      pack_name = models.CharField(max_length=100)
      pack_description = models.TextField()
      pack_duration_days = models.IntegerField(default=0)
      pack_cost = models.IntegerField(default=0)      
  
  class selected_packs(models.Model):
      user = models.ForeignKey(User)
      pack = models.ForeignKey(avail_packs)
      activation_date = models.CharField(max_length=100)        
      quantity = models.IntegerField(default=0)
  </code></pre>
  
  <p>assume there is a pack say bronze</p>
  
  <pre><code>pack_name=bronze
  pack_description='1000 newsletters'
  pack_duration_days=30
  pack_cost=9.9$
  </code></pre>
  
  <p>if user activated a pack </p>
  
  <pre><code>user= User.objects.get(username='suhail')
  pack= avail_packs.objects.get(pack_name=bronze)
  activation_date= 27-aug-2013
  quantity=1
  </code></pre>
  
  <h3>now my question is what i want to do the item in selected pack on date <code>26-sep-2013</code>?</h3>
  
  <p>do i need to delete the item(delete item from selected_packs where <code>today-activation_date&gt;29</code>).</p>
  
  <h3>if i want to delete the item then how?</h3>
  
  <p>do i need to run a cron(<code>django celery</code>) and check every day to delete these items.</p>
  
  <p>or do i need to delete the item when user clicked the newletter(or some chargable items)</p>
  
  <h3>i am using paypal so is there any method in paypal to do these types of monthly subscriptions?</h3>