How to find out when your T-Mobile contract is expiring?

Sometimes you want to know when your T-Mobile contract is expiring, either because you want a new phone, want to switch providers, or just because you think they screwed up. And if you asks this completely reasonable question to T-Mobile, they will tell you that you need to call them up to learn this information, and also, "Is there anything wrong? Why are you curious?" Annoying.

To find out when you contract ends do the following:

• Go to t-mobile.com
• Go to the "My Account" section and log in.
• Look for "My account activity" and select "More account activity" and go back far enough in history to find the most recent "Change in contract" event. Expanding this event will tell you what date you contract was extended to. 
• (The list only keeps 24 months of activity, but if there were no "Change in contract" events during this time, you almost certainly have finished your contract.)