Always. If you buy an EVGA card, you can then buy a new card off the website within 90 days and only pay the difference, no matter what you paid on the first card.
All you have to do is register the card, fax or email them a receipt when signing up for the Step-Up, and when you get approved, just mail in your card and wait for the new one. But you have to cover the full cost of the new card until they get your old one and mail the new one, and they DO wait for your old card to show up. So you're left with no card for a week or so, but you save a ton of money.
Only caveats are you only get to do this once, and they reserve the right to deduct up to 15% of the first card's purchase price if you don't have things like the original packaging, or there are parts (cables, etc) missing. You also need the original driver CD in there, too. But frankly, it'll only be $20-$30 max. Small price to pay.
Yeah, it'll suck not having the card for a week, week and a half, but you'll save a ton of money, especially if you're using higher-end cards.