Just did a few sums. As you do and now I'm surprised how low your maximum steps in a day figure is.
MrsG uses a step counter and it registered close to 23000 steps on a 7.1 mile walk, with hills on farm tracks, on Saturday. So by scaling that up to a 25 mile walk in mountainous terrain. I could see it easily hitting 80,000+ on such a day hike. Baring in mind going up and down on steep ground, steps are likely to be in the 12 to 20 inch range. ie 3-5000 steps per mile.
100% agree the counters are good for motivation.
I'd be interested to see your sums...
According to Garmin (and my own measurements) my average stride length was 0.93m (or 36.6 inches) measured over the 248 walks I recorded last year.
On normal solo walks, I do about 17,000 steps in 10 miles, which is very different from what your wife would do!
On that record-breaking day last year, I did a 31.6 mile walk with my wife.
If that walk had been a solo walk, I would have done around 54,000 steps (plus any others on that day). However, when I walk with my wife, I go a bit more slowly and my stride length is shorter - hence the extra steps recorded that day.
The previous year, I did a 32.3 mile solo walk in 7 hrs 55 mins, and the step count (for the walk plus the rest of the day) was approximately 56,000 steps - my daily record at the time. The 31.6 mile walk with my wife took 9 hrs 50 mins, which was much slower and resulted in a shorter stride length and consequently increased number of steps.