Tesloop released a very interesting review and summary of using "eHawk", the 2015 Tesla Model S over 450,000 miles (724,000 km), which is one of the highest mileages globally.
The car was used for 17,000 miles (27,000 km per month) at its peak, constantly using Supercharging as its primary charging method.
After such high mileage, the Model S has a noticeable amount of wear and tear inside and outside, but overall it's not bad and still drives well.
According to Tesloop, the eHawk had three major replacements under warranty (described in this earlier post):
Front Drive Unit - 36,404 miles (Warranty $0)
High Voltage Battery Replacement - 194,237 miles (Warranty $0)
High Voltage Battery Replacement - 324,044 miles (Warranty $0), replaced after about 130,000 miles
The third battery pack has been used currently for close to 126,000 miles (202,777 km) and because of a change in driving profile, battery degradation is slower than earlier.
Here are the costs of service:
Regular Scheduled Maintenance (RSM) - $12,782
General Vehicle Repairs (GVR) - $14,823
Total Cost $27,604 ($0.07/mile)
Taking into account electricity cost (info below), the total cost stands at $74,404, which is $0.19/mile.
"MSRP Fuel Costs, 2.5 miles/kw, @ $0.26/kw for 450,000 Miles $46,800.00
Disclaimer: This vehicle is grandfathered in with free supercharging for life."
Maintenance logs for eHawk can be seen here: http://bit.ly/2w8OHvX