We are no experts in dehydrating, but we do dry a lot of apples and pears and they keep us in snacks all year round. Unlike most people we don't core them, or remove the skins as these are the most nutritious parts of the fruit. Although you might think the core and pips are a bit tough to eat, once dehydrated they taste much like the rest of the apple, chewy and delicious.
We don't dry vegetables as we find it's much easier to freeze them, or turn them into preserves of one kind or another.
To dehydrate apples and pears we get a bowl of water, into which we put a teaspoon on Vitamin C powder (lemon juice works too, but costs more) this stops the fruit from browning.
We then slice the fruit, having removed the stalk. Everything get dried. When I'm doing the dehydrating my slicing isn't very accurate, but it doesn't matter that much. Aim for about 7mm, but 5-9mm is fine. When you start the dehydrator I turn it to 70c for 30 minutes, this kills any nasties.
The actual time taken to dry the fruits varies, it depends on your dehydrator, the variety, how ripe it is, the temperature you dry at, the ventilation levels and the thickness and size of the slices. Lots of variables. However once fruit has dried it doesn't mind that much being dried for another couple of hours, so you have quite a bit of leeway. For apples and pears with 13 hours at 50c. Then eat a thin slice and a thick slice, you will quickly learn to taste moisture, do another few hours and then eat another couple of slices.
Once you train your brain to recognise a well dried slice, you are sorted.
This is the dehydrator that we use, it's nice and compact and it has metal trays, which I recommend.
We store all of our produce in mylar bags, that are clear on one side, so easy to see what's in the bag.
<aside> 💡 Here's a rough idea of how long different foods take, but don't trust the timings, trust your taste!
</aside>