I'm new NW silver elite member (will be gold by end of next month) and will likely focus on flying NW next year to maintain status unless there are huge negative changes in the program.

But I keep getting all kinds of solicitations from other airlines sponsored credit cards (AA, United, etc.) to pay somehwere between $50 and $70 for a credit card for a year, and then get "5,000 miles and a free companion ticket" or something like that after my first credit card purchase.

Are these miles I shouldn't pass up, even given the fee, e.g., just in case I decide to eventually switch to AA or United or whatever airline is soliciting? Or do many of you throw these out (given the fee), they're just not worth the "insurance" and would result in orphan miles?

Related to this: is there still a good way of getting something out of orphan miles on multiple airlines (other than building up the individual accounts into a free ticket)?