the objective of the question was to determine if the property was used for personal use.
That's what I looks like to me. What I've found in some experimentation a few years back, was that if you did not count vacancy between renters, it made no difference in any of the numbers as far as depreciation and allowed expenses go. However, if you have personal use days, that does make a difference and reduces the amount of depreciation you're allowed to take.
