If you cut into the bars before they are fully cooled, they will stick to each other. If you intend to eat them within two days, the bars can be covered and left to sit out at room temperature because of their low moisture content. The more sugar a bar contains, the safer it is to store it at room temperature because the sugar absorbs moisture and creates an environment that is hard for bacteria to thrive in. If they are going to be consumed over a longer period of time, you will need other options.  Vacuum seal individual bars to keep them at room temperature. The oxygen free environment reduces the chances that bacteria can grow. These can be kept in a cabinet for up to 5 days. Refrigerate the bars. This is the safest and best way to store them. In the fridge, the bars can last 7 to 10 days. Be wary of other foods in the fridge because the bars may have a tendency to pick up volatile flavors, like onion, which can ruin their taste. Freeze the bars. Bars can be frozen for an indefinite period of time without worry of microbiological contamination. However, the quality of the bars will degrade. It is best to freeze homemade snack bars for up to one month for optimum quality. Freezing will slowly dehydrate the bars, and, since they have so little moisture to begin with, too long in the freezer will cause them to crumble. Also, the moisture that comes out of the food can cause ice crystals on the surface of the food, which acts like a knife to the food breaking the texture. 
Cut the bars once cooled completely. Determine the best way to store the bars. Finished.