This relates to another question that was just recently asked:
What kinds of materials does DDI give you that you retain access to "offline" (including if you were to let your subscription lapse)?
At one point the Dragon and Dungeon magazines were called out as being available as PDFs at the end of the month, but I haven't seen mention of this elsewhere. If so, are you able to get access to older magazine issues from before your subscription started? Do Character Builder updates stay valid at the point you last updated them, or do you have to connect to get them to work?