I posted this yesterday on Tesla's forum site. After a few comments from others, it was deleted today, which only heightens my disappointment. I'm posting it here to assist new buyers in avoiding an oversight I made: I was progressing though options to "trade up" my 2016 Model S 90D for a 2016 Model X P90D. On the 89th day of my Model S lease I received the Happiness Guarantee in an email; in other words, one day prior to expiration. Exiting my Model S lease and purchasing a Model X (else waiting the required six months before entering another lease) WOULD HAVE been a viable option had I received notification and relevant paperwork earlier than one day before expiration. My Model S is a magnificent car, but after a couple months' use, we realized we really needed an SUV (Model X). Now the Happiness Guarantee return is no longer an option. It doesn't seem very "Tesla-like" to avoid disclosing the Happiness Guarantee until 89 days into the lease. I'm disappointed.