18 months?

I probably did not make myself clear. I dis't mean how long after cancelling a card before I can reapply for the same card/same offer and try to double dip.

I meant, how long does it take after cancelling some cards for my credit report to show the accounts are closed, to improve my chances when applying for new and different card offers from other banks, banks that have previously been skittish about my large number of open cards and large amount of available credit.