A Hilton credit card, Visa or Amex, is the best way to keep a Hilton account active. Both cards have no annual fees. Hilton, unlike Marriott, is pretty aggressive about closing down accounts that do not generate activity within their requirement of 12 months. Marriott reserves the right to close an account that has been inactive for 24 months, but I have yet to hear anyone actually have their account closed for that reason.