Do I need a 0.1g scale or is 1g accuracy good enough?

For everyday cooking and most home baking, 1g resolution is what virtually every mainstream reviewer and baking-subreddit thread recommends, and it's what the top picks here use. Sub-gram resolution (0.1g or 0.01g) really only matters for pour-over coffee dosing, espresso, sourdough starter ratios at small volumes, or weighing yeast and spices, and in those cases a dedicated pocket or coffee scale is the standard advice.