The moisture content will vary depending on the type of apple you are using. That’s why it is essential to keep an eye on the apples as they are cooking, in case they dehydrate faster or slower than average.  Keep in mind that the chips will not be crunchy right when you take them out of the oven. Let them sit for 10 to 15 minutes; magically, they will have crisped up!  They may need 10 more minutes in the oven if they haven't. Be careful not to overbake them because they will crisp outside the oven.