I am trying to be efficient with my battery consumption, so I often turn my motor off during rides, when I don't need it. Does it wear the motor out over time, if I turn it on and off constantly during rides? Or is it better for the motor's life expectancy if I keep it on, and leave it on Eco whenever I'm on flat/downhill roads? I live in an area where there are many hills.
Update: I own a Specialized Turbo Vado 3.0. I often set my speed to 0, which I think turns off the motor, whenever I am on a downhill or long stretch of flat road. But that means switching between 0 and the other 3 modes. I wonder whether switching back and forth between 0 and the other modes often can wear the motor. Hope this clarifies.
I don't know the Vado specifically, but I agree: Go ahead and set assistance to zero whenever you are on level terrain or going downhill. I don't see any other solution for longer rides. Hard to imagine how this could hurt the motor. What I would NOT do, as everyone else is also saying, is shut off the bike completely, just for safety reasons-- if you suddenly want assistance, you can get it more quickly if you don't have to reboot the controller, which takes about 5 seconds on my bike.
I also live in a neighborhood with steep hills, and if I want to stay off city streets, there is almost no 10 mile ride that doesn't involve 1,000 feet of vertical. For rides over 30 miles, I always dial down the assistance to zero for flat or downhill terrain, though note: Once you've reached maximum downhill speed you are comfortable with, you're coasting and not using battery anyway no matter what mode you are in. Thus, if I want to go really fast, I might start a descent at max assist to ramp up to high speed quickly, but once I've reached about 20 MPH, the assistance cuts out anyway. So I might wait until later, when I'm on the flats, to set assistance to "OFF." (This is also because at 35+ MPH speeds, I want to be totally focused on the road and traffic.)
There's a route around the Hollywood reservoir that's pretty flat. If I have plenty of juice, I'll take the whole thing in Eco at 17 to 19 MPH because it's just more fun to ride fast. But if I'm getting close to reserve, I'll take it at 11 to 13 MPH with the motor off, and obviously that saves a lot of juice.
Similarly, to extend range, (you may already know this), go slower going uphill, downshift, use a high cadence with a circular leg motion, trying to deliver power from your foot to the pedals even as you backpedal/pedal upwards (I don't use clips, but use high-traction shoes), and use as little assistance as you can stand. In Griffith Park, sure, I'll have fat bikes-- and sometimes even roadies-- passing me going uphill, which feels weird, but... they're probably not going on 30 mile rides!
When I first got my bike, I estimated it's max range at 35 miles.
16 months and 700 miles later, I have hit 42 miles with some reserve. I estimate total range at 45 miles with 5,000 feet of vertical-- and one hell of a workout!