I drive mine exclusively in low always.
So do I. While it doesn't increase the amount of regen possible, it makes it more probable that you will get more of the regen by not having the blended braking if the brake pedal start using friction braking sooner. Unfortunately, the "brake score" that is displayed only does its calculation when the brake pedal is pressed for at least several seconds. I do like the increased deceleration without brake lights to get a tail-gaiter to back off.
I've had my 2017 FFE for 7 years and one month now, and I'm nearing 158,000 km. The battery warranty ends at 160,000 (100,000 miles) which will probably be sometime in February. I'm finding the range is pretty much as it was when new, about 120 km in the winter and close to 200 km on warm but not hot days (Toronto weather).
I've had a few repairs needed, naturally after the extended warranty ended, but that's my fault for missing that the six-year warranty had only 100,000 km and not 150 as our ICE Focus had. One was a coolant diverter valve (the FFE has two of them). I had the old one returned to me and I opened it to find one wire to its motor broke off, so now I have a spare.
I had the right wiper motor fail. Good thing the FFE uses separate wiper motors, since the working one left the car drivable in the rain while the replacement was on order. I replaced it myself easily enough and calibrated it with Forscan.
The most expensive repair was the A/C evaporator which started to leak a year and a half ago. On an ICE vehicle, I might have lived without A/C, but an EV needs it to cool the battery. I want to get another two years out of the FFE to make that repair worth the cost.
I've also had to replace the HID headlamps. As for brakes, only the front pads and rotors were replaced at 133,000 km. The pads had nearly 4 mm left, so they could have lasted longer, but the rotors were pretty pock-marked from little use (this past week, the lifetime regen total just hit 20,000 km). For comparison, our ICE Focus had all four brakes done at 65k and again at 128k.