There are a variety of sites you can use to track your data related to training. I used Training Peaks extensively last year because I was working with a coach and that was what she used. I always use Garmin Connect as the first place I put my data because it sends it out to the other sites like SportTracks and Strava. And now my Garmin 920XT will send it via my phone without me doing anything!
I am not person who likes to repeat steps so I have to keep this part of my life as simple as possible. I will not update my data in many different sites so I have to choose one (or two) sites to keep as my “source of truth”. I am making a resolution NOW for 2015 to have those sites be Garmin Connect (because it works so great from my phone and it has to start there) and SportTracks. I will be using SportTracks in addition to Garmin because it offers me two functions I find helpful.
First, I can set up a training plan in the site so I can keep track of what I have to do. They don’t have an app for the phone yet but they have optimized their website so it is “Mobile Friendly” so I can have my plan with me at all times. It even sends me an email if I miss a workout!
Second, I can easily track gear usage. I am notoriously bad about doing this. Since this year is a run focused year, tracking the mileage on my shoes is quite important. I am getting a jump start now and plan to be diligent about this in 2015. I will be estimating my mileage on the bikes as well so I can track them in addition to my shoes.
SportTracks is not a free service but it is fairly inexpensive and has LOADS of features. I highly recommend it.