You could always rent a vehicle for your remaining driving needs. For 10% of total driving that might be somewhat impractical, but 10% sounds like a pretty high estimate for trips that would challenge the Model S's range. That's one long-range trip every week and a half. Yes, there are people who drive like that, but they are very much in the minority.
If you drive to grandma's/the in-laws/"up to the cabin" three or four times a year, that's only 1% of trips (assuming you commute every day and run local errands on the weekends). Most families in the US already have multiple vehicles. Why can't one be an electric?
If you drive to grandma's/the in-laws/"up to the cabin" three or four times a year, that's only 1% of trips (assuming you commute every day and run local errands on the weekends). Most families in the US already have multiple vehicles. Why can't one be an electric?