The shelf life of store-bought pasta sauce after opening the jar can vary depending on the specific product and brand. In general, an opened jar of pasta sauce can be stored in the refrigerator for about 5 to 7 days. It's essential to check the label on the sauce jar for any specific storage instructions or "use by" dates provided by the manufacturer.
To extend the sauce's freshness, make sure to always reseal the jar tightly after each use and store it in the refrigerator. If you have a large quantity left that you won't use within the recommended timeframe, consider transferring the sauce to an airtight container and freezing it for longer-term storage. Frozen pasta sauce can last for several months and can be thawed and reheated when needed.