Hi.
From 1976 to 2004 I drove with no economy in mind: I drove like it was stole and got about 16MPG in a Dodge Spirit 4cyl which EPA rated about 24.

When our family moved out to the rural area, creating a 50 mile commute I had to find a better way. I tried driving more efficiently but just got bored and returned to the old normal way.

We replaced our 10yr old Dodge with a Civic Hybrid CVT(AT) in 2004. I didn't buy it to "Save the planet", but because gas had recently exceeded $1.00 /g.

Intrigued because my mileage was about 50MPG, I wanted to see just how high it would go. I did a lot of experimenting and web research and began hypermiling. (Google hypermiling if unsure)

After two years of "training" I was able to reach my personal record as posted in my signature below. The long commute and off-hours were a major contributor.

Since then my hours have changed and join the other folks in terrible Atlanta rush hour freeway traffic. Although my efficiency efforts are scaled back, I still average above 60MPG using the tips here:
http://www.automotiveforums.com/vbulletin/showthread.php?p=5752366#post5752366

Today it has +120,000 miles and starts/runs/drives as new. Had zero problems with it. Tires lasted till 88,000 miles and original brakes have "Plenty" left on them.
I usually get bored with vehicles after the 1st year, but after 4 years I still love the car, love to drive it and take good care.

So how much money have I actually saved? It's difficult for me to calculate.
Being an ex Dodge patron, 2nd runner up was a Neon. I understand most folks average about 26MPG with it.
The closest comparable regular Civic (EX) was about 1,000 less with mid 30's MPG.

I say it's difficult to calculate because if I'd have bought a regular Civic or Neon, I would still have no thought what-so-ever of driving efficiently.
There is no doubt I'd be doing mid 20's MPG in a Neon or Civic- and have a beat-up wore out car again today, shopping for a replacement at 120K miles.

Also considering that I've transfered the lessons learned in the Civic Hybrid to our Grand Caravan with good success, all that I can say is that we've saved thousands in fuel over the last four years.

So what do I do in the future for battery replacement? That seems to be the most prevailing question people have.
If and when it needed replacement I could:

1. Do a new Honda replacement, which includes all the controller equipment for about $2,400

or

2. Replace it with a guaranteed used one

or

3. Just drive it with a flat hybrid battery (But reduced performance)


-Steve

Wow! 75 mpg! That awesome with a Civic Hybrid!

For your question, I suggest you to drive it with flat battery until you got tired of it. Then replace the car.