This piece of advice is straightforward. Never order sushi at an empty sushi place. If a restaurant is empty, there’s usually a reason. The food is probably not that great, and their ingredients are most likely sitting out longer due to slow business. Low-quality sushi is not something you want to mess with. It’s basically asking for a stomach ache!
Also, avoid ordering sushi on Sunday or Monday. Restaurants usually get their fresh seafood deliveries on Monday afternoon or Tuesday morning. This means that the fish served on Sunday and early Monday is on its last leg of freshness. This is a pretty useful tip if you’re a sushi lover!