Other North & South America Frequent Flyer Programs - Spirit CC downgrade to Plat from World?

I want to keep a spirit CC so my miles don't expire because I think if you show activity every month (perhaps once every 3 months) I don't think the miles expire.

I don't want to pay $59 for their crap World MC when the free year ends.

Has anyone downgraded to the Platinum Plus card with the $19 fee and been able to keep the miles active?

Usually if you call the CC at the end of the year... they may waive the fee for you as a courtesy.