Honda is releasing their 123
Honda is releasing their 123 mile range FiT EV which will use Toshiba SCiB lithium-ion batteries.
The SCiBs are rated for 4,000 cycles. 4,000 cycles x 123 miles = 492,000 mile battery life.
Doesn't seem that battery replacement will be an issue. It might be that you would transplant your battery pack into your next EV. (As long as their isn't some sort of calendar lifespan for the batteries.)
--
GM and Nissan are guaranteeing their batteries for 8 years or 100,000 miles. So even with those EVs your 5 year battery life is on the low side.
--
Here's what GM has to say about premium gas...
“The Volt is all about efficiency,” ( Volt vehicle line director Tony Posawatz) said. “Premium fuel offers the opportunity to have a little bit more spark.”
“Ninety one octane fuel also offers the opportunity to be a little more efficient, he added. “So technically its a five to ten percent fuel economy improvement the few times that most people will run the range extender.”
Posawatz also claimed the increase is cost will be offset by the efficiency gains.
“Based on our calculations the fuel economy and efficiency gains you get will effectively compensate for the extra cost of premium fuel,” he said
Additionally, premium fuel is apparently slower to go stale."