I find it difficult to extrapolate too much but it is fun.
This morning, I made it the 9.0 miles to work on 5% on my 2017 S. Google maps shows the elevation gain/loss as +374 ft and -36 ft so basically flat (for CO standards). There wasn't much wind and I did hit all the green lights but it was a pretty normal day. I usually use about 10-11% on the way home since the traffic is faster and more aggressive at that time and maybe I'm just in more of a hurry since I'm heading home instead of heading to work
There is often a slight wind off the mountains then that causes a head wind in the evening also. It's not much but you can feel it on a bicycle and I ride this route fairly often to work and back.
And yes, it was really 5%. If I could have done it on 4% it would have been a new record and I was momentarily at 4% while using B-mode getting off the highway but it went back to 5% when I had to accelerate up the hill to the parking lot at work. This was between 51% and 46% of charge based on what the dash shows. I haven't noticed a big difference at other SOC's but I'm just starting to keep track of this stuff.
So my 30kWh pack will be fine for me even though I think it will be replaced under warranty at some point. I have 41xx miles on the car and it's about 9 months old and I'm already at 92% SOH according to LeafSpy.