<font face="Verdana, Arial, Helvetica, sans-serif" size="2">Originally posted by Mrukk:
Hmm, and one more question... I signed up for a program (Delta) a couple of months back, and have 18,000 or so miles at the moment. Do I still have to fly several more miles by the end of this calendar year, or would I have an extended qualification period based on my signup date? Or should I be talking to Delta about this? 
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Now that you have the basic knowledge, take your Delta specific questions to Delta forum, as the folks there would be able to help you out better than here.
Good Luck!