When cooking baked potatoes I usually cook extras (in tin foil) because there are so many things that I can do with them.  After they’ve cooled I usually put them in the fridge but then have to take them out to warm up for using.  However, my husband said it would be ok to leave them on the counter until ready to use.  I wanted to find out what is the proper way to store already cooked potatoes. I’m sorry to say that your husband loses this argument.  Think about potatoes wrapped in foil just like you would when canning vegetables.  Would you cook the vegetables and put them in a glass jar, seal it up and then leave it at room temperature? The food safety issues are very similar.  Not that long ago there was an issue where a restaurant took leftover baked potatoes and decided that even though they only were left out overnight at room temp that they would be fine to incorporate into a Greek dip called Skordalia. Several people got very ill. The foil potatoes stored this way can cause botulism. Don't do it.