Try to consume the paneer within several days. I have cooked with the cheese about 6 or 7 days later, and it was fine. If you leave the paneer in the fridge for too long, it will start developing a light peach/pink color, and that's a sure sign to toss it out. Make sure to remove the cheese from the cheesecloth and store it in an airtight container. Do not store the paneer in the refrigerator when it is just wrapped in the cheesecloth as the cheese will dry out. You can freeze the cheese for up to several months.