If you're a store owner or manager, you can have a special role to plan when the sh*t hits the fan, if you choose to. If your store has food or merchandise that is helpful for survival situations, you can methodically secure your store and establish a barter location at the start of the collapse to help yourself and many others.
First and foremost, you should be concerned with the security of your family, yourself, and your employees if they are still with you, so if at any time you feel like it might be too dangerous, just leave to be with them and retreat to a secure location.
Once you are sure the society will collapse (by this time the electricity will be out, credit cards aren't processing, the water is not running in the pipes, and the police have lost control), you should organize your employees and friends to act as an armed security force protecting your store. Prevent looting. If people want something from your store, they will have to bring you something that you want in order to trade for what they want. It will become an overnight barter trade center. Before you start trading, however, you should set aside the items that you want to keep for yourself, your employees, and any of your security force. You can create a list of all your desired items that you are looking to trade for so the visitors can know what they can bring you in order to get what they want. If you are a store that has lots of food, you will probably be willing to trade for survival gear. If you have lots of camping gear in your store, you will probably be willing to trade for food. You can also think about trading for alternative energy, livestock, seeds, garden plants, etc. If you have meat and produce in your store, you should begin preserving it. You might need to even build a smokehouse next to the store, although, I think a dehydrator is a better option.
When most of your items have been traded or things become too dangerous, you should abandon the store and retreat to a bug out location. I would recommend leaving within 1 week of the beginning of looting. If you wait much longer, powerful gangs will rise up and the chances of a confrontation with them increase dramatically.
If big stores like Walmart and Costco implement this method, they can actually become major centers of trade if security is maintained for long enough. But I think the combination of gangs, the starving masses, fires, lack of fresh water, and lack of farmland nearby will prevent these large stores from remaining trade centers long after the collapse.