I just bought a brand new Accord Sport with manual transmission. The dealership told me to run it in ECO Mode all the time. That doesn't make sense to me or my husband. My husband is wondering if by running it all the time is it hurting the car. The manual only says if you see the leaf, it's on.

 

It won't hurt the car to leave it on all the time. But it'll limit the power available and if you had an automatic transmission it'll change the shift programming.

I'd say try it both ways to understand the difference how it behaves, then decide. You'll get better gas mileage with it in ECO mode, and maybe you'll want to sometimes switch it off when merging on a highway or something.