If you have opened a can of beans and transferred the leftover beans into a sealed container, they can typically last in the refrigerator for about 3 to 4 days. This assumes that the beans were cooked properly before being stored and that the container is airtight to prevent contamination and moisture loss.
To maximize their shelf life, it's essential to store the beans at a consistent refrigerator temperature, which is typically around 40°F (4°C). If you're unsure whether the beans are still safe to eat after a few days, use your senses to check for any signs of spoilage, such as an off odor, mold growth, or an unusual texture. When in doubt, it's safer to discard the beans to avoid the risk of foodborne illness.
If you don't think you'll be able to consume the beans within the 3 to 4 day timeframe, you can consider freezing them for longer storage. Properly frozen, cooked beans can last for several months in the freezer. Just ensure to use a freezer-safe container or freezer bags and label them with the date to keep track of their storage time.