I did this - wore a pedometer and wrote down the number of steps each night for a month. It was interesting. During the first week, it let me see that my intensely active lifestyle (as I saw it) was really a sedentary one. I added each day from the day before until I reached 10,000 about 5 days a week.
Did you see the study about the Amish? Researchers had a group of Amish people who had very little incidents of Western diseases . . . the average Amish woman walks 14,000 steps (7 miles), Amish man walks 18,000 (9 miles) and an Amish man following a horse and plow while working in a field 51,000 (25+ miles).
A few habits that are now ingrained in me from wearing the pedometer . . .
I always take stairs
I park the furthest away in a parking lot
I pace when I am talking on a phone
I take extra trips instead of trying to carry things in one arm full
Sandy