There was a time when the Citi Prestige was my absolute favorite of the premium credit cards that give you a ton of value on travel. Citi announced changes last year that greatly devalued the card's benefits while leaving the hefty $450 annual fee in place. The last of those changes take effect in July 2017, and - sadly - I wonder if it is time to cancel this once-great card. Here's what you should consider if you're thinking of cancelling yours.