Do you own or use a pedometer?  

I always like to take my pedometer when I go walking, it tells me how many steps I take, how many steps contributed to aerobic exercise (it usu. takes about 10 minutes to get going), how far I've walked (distance & time), and how many calories I've burned.
I think it's very helpful b/c if I have 900 steps for instance, I'll walk another 100 to get that perfect 1000 steps (or if I've walked 23 minutes, I'll usually walk another 7 so I have 30 minutes).