Is this a trick question? Pay the AF when the benefits are greater than the AF. But quantify benefits truthfully. Consider Fido Amex / Citi Double Cash (2% on everything) as the alternative to everything. So only calculate the amount of rewards that beats 2%, because you are giving up the opportunity to get 2% cash back by using a different card. If there are other card benefits that you profit from (i.e., free checked bags from an airline card), then include them in the valuation. But avoid the "and there are other benefits I like so the card is obviously worth it" argument.