During the last year, I've been using Fitbit Flex. This great activity tracker strap is quite accurate; I was quite unsure at the beginning, I still remember me comparing the Fitbit log against the machine one, and surprisingly there were low rates differences (mostly, less than 10%). Alongside the tracker, Fitbit provides a great API to see your logs and after 6 months of use, I saw mine. Bang.
I was overwhelmed when I saw the result, also considering that during May I was travelling and walking approximately 10km per day.
* My calculation was 1,158.93 + (10 km * 30) = 1458 -> 1500km in 6 months! *
Indeed, I understood why I replaced 3 times my running shoes. To avoid any kind of sore, firstly I decided to do a foot analysis test.
As you can see in both pictures (L/R), if you do that to your body for 1500 km using incorrect shoes, things can not go well. Therefore, correct shoes (and not the fancy ones) are essentials.
I recommend you to use it for some time. I think it's a great value for the price. Also it helps you to see your lifestyle and how much you move daily.