Greetings -
Like many others I've wondered about resale value for my M3, and frankly don't expect high value retention given the constant changes in list prices/configuration options, vanishing Tax Credits, and Tesla's tendency to make "special pricing deals" at times when they need to generate extra revenue.
I looked at Tesla's lease options, made available yesterday, to see how Tesla views this. I used a LR AWD model, now with the new "standard" autopilot included, in basic black color with no other options. Tesla specs that car at a price of $49,500 (pre transportation/doc fees, exclusive of state taxes/fees - as do other manufacturers). The lease requires a $3,000 down payment and 36 payments of $674. Tesla also notes that there is no option to buy the car when the lease ends (and I assume that there is therefore no tax benefit to lessees).
So, the 36 payments total $24,264, adding in the $3,000 down payment, the total payments are $27,264. To make the math easy (there are time value of money considerations, implied financing, etc. - none of which I'm considering) that means that Tesla expects the car to be worth $49,500 less $27,264 when the lease ends (again, they expect it to be worth more if you allow for implied financing and various carry costs).
Given the simple example above, Tesla believes the car's residual value will be approximately 45% of the new price at the end of three years. Again, lots of things to add to the calculation - tax credits among them, at least for now as Tesla will get them as the manufacturer.
So if Tesla expects the cars to drop in value by roughly half in three years, it seems that none of us should expect residual values to be dramatically higher than Tesla's own estimates. Their residual estimates don't surprise me, and aren't all that different from European brands. It just confirms what many have said before - Tesla is a unique car that many of us enjoy fully, but they are not investments, and shouldn't be expected to have lower depreciation than competitor cars.