I rent out a guest room in my apartment on Airbnb during the summer season (not full time). I am a renter, not an owner, of the apartment.
As I understand the above statement, you do not own any portion of the property you live in, or rent out. You yourself are a renter of the entire apartment, and you "sub-let" rooms out to others seasonally. For this part, the important thing you understand is that while you are required to depreciate rental property that you actually own, you can not depreciate property you do not own. So when asked for your "cost basis" (how much you paid) for the property, your correct response will be ZERO for both "Cost" and "Cost of Land".
Now if you personally paid for any qualified property improvements (I would seriously doubt this, since you don't own the property) then you would be able to report what you paid for those improvements, and depreciate them.
The bedrooms are always listed for rent on Airbnb, but I use all the rooms in the apartment for "personal use" when I don't have bookings.
The questions being asked that pertain to days rented and days of personal use only apply to the rooms being rented. Nothing more. Nothing less.
Earlier, when answering the questions, I tried to say that guests used the property 29 days and that I used it for personal use for 365 days
The total number of days (personal plus business use) can not exceed 365. Therefore, since you do state that you use the rooms when there are no guests, your days rented would be 29 and your days of personal use *of those rooms* would be 336.
