How long will apples last, in and out of the refrigerator?

Here’s the answer, from food scientist Susan Brewer: “The longevity of an apple is determined in part by its water and sugar content.  Hard winter apples, which have a lower water content, last longer than summer apples.
 
“The shelf life of all produce also depends upon the variety, how ripe they were when picked, and how they were stored after picking and prior to distribution to the retail store.  Hard winter apple varieties (such as Granny Smith), which are picked underripe and stored at refrigeration temperature in modified atmosphere called MAP (not the same mix of oxygen, carbon dioxide, and nitrogen as in “air”) can be held 6-12 months before they reach the retail store. This is why they are available in July.  Summer apples, which are softer and higher in water content (such as Delicious), are commonly picked nearly ripe.  If stored in MAP in a  cold environment, they will last 3-6 months.
 
“Apples are usually sold either such that you can choose the individual fruits from bins or in bags punctured with holes.  Apples produce ethylene gas which hastens ripening, so they should be allowed to “breathe” and should be stored away from other fruits.  Loose apples will last  6-8 weeks if refrigerated.  If they are on the counter, they ripen 10 times faster because the enzymes are much more active at room temperature, so they will keep for a week or two maximum.”
 
Source(s):
Susan Brewer, Ph.D. University of Illinois, Department of Food Science and Human Nutrition