You can use things like 17% annually or look at the resale of a 3 year old Model S. Or google tesla depreciation and see what others think. My best guess is more than 40% and less than 60%.How can I estimate the trade-in value of a finance purchase versus the guaranteed resale value at the end of my lease? My intention has always been to traded in after three years for the 'newest' larger battery and second generation of AP hardware.
Also if tesla guarantees a resale that means they think they can sell it as CPO for more than that so you should be able to sell privately between those 2 figures.