Yes, the dealer's up card does change your strategy in blackjack. If the dealer shows a card between 2 and 6, they're more likely to bust, so you can play more conservatively, standing on lower totals like 12-16. When the dealer has a strong card, like 7 through 10 or an Ace, you're at a higher risk of losing, so you may need to play more aggressively, hitting on totals like 12-16 to improve your hand. The goal is to adjust based on the dealer’s potential to either bust or make a strong hand, with the most cautious play being when the dealer has an Ace.