I swear LG and Jet Dry were in cahoots when my dishwasher was made. I know dishwashers these days often come with a built in spot for rinse agent, but actually using it is supposed to be optional. My dishwasher literally won't run the drying cycle if the rinse agent compartment is empty. I am not a fan of spotty dishes, but I am REALLY not of fan of hand drying everything.
Jet dry also seemed to be one of those things that I always forgot at the store, so I was always out of it. Thus began my quest to find a way to trick the dishwasher into thinking the rinse agent was present so that it would at least run the drying cycle :-) Lucky for me my first experiment turned out better than I could have ever hoped for.
I haven't bought Jet Dry, or any other rinse agent, for over a year now!
Just use vinegar the same way you would have used Jet Dry and you will end up with the same sparkly glasses for a fraction of the price!