What size pressure cooker should I buy?

Reviewer consensus across r/instantpot and r/PressureCooking lines up around 6-quart for couples and small families, 8-quart for batch cooking and households of 4+, and 3-quart for singles, dorms or as a second pot for sides. Several long-time users on r/PressureCooking specifically warn that the 6-quart can feel small once you start cooking roasts or doubling recipes.