I don't think doing 10,000 will make anyone healthy per se...but 10,000 is a good goal to have if you find that you don't walk that much. At school I average about 3,000-4,000 depending on how much I'm walking around. By the time I'm home I've done about a mile. It takes a little over 2 miles to do 10,000 steps. 10,000 steps is hard to reach if you're not going out and doing some extra walking. But 10,000 is a good goal to have, and once you reach it, you can try to do 10,000 steps a day on average. And then you just compete with yourself.
You see...it all depends on how busy your day is. I didn't exercise everyday this week.
3998, 11741, 4755, 5613, 10489, 5295 have been my numbers so far this week. And this is just steps in general. The higher days are the days I went out for a walk. The 3,000-4,000 day is where I didn't do much walking.
You should set a number goal for yourself. For me, I suppose my goal would be to do 8,000 everyday, or even 10,000. I just try to do one mile a day aerobically. I don't worry so much about the steps.