Use a rocks glass when the drink is compact: an old fashioned, a small sour, whiskey over ice, or anything you want to smell as much as sip. Use a highball when the drink needs height, carbonation, or lots of ice. If cabinet space is tight, keep six of each before buying specialty shapes. That small set handles weeknight drinks, mocktails, spritzes, and water for guests.
The Glass / Glassware
Rocks Glass vs Highball Glass: What to Use and When?
Short glasses suit spirit-forward drinks; tall glasses make room for ice, bubbles, and slower sipping.