Perhaps a question best asked of Rob and Melanie, but speaking for myself; I have had unopened jars, upright, on the shelf, for six months or more. Once I open them they go into the fridge, where they have stayed for weeks, sometimes months. I always make sure they are covered in brine, topping up with olive oil and water as needed (I have virtually never needed to top up a jar).
BTW, I have used the brine as a substitute for water when reducing sauces in the pan, and also in vinaigrettes, so sometimes I keep the jars in the fridge, even though there are no olives remaining.
