How do I see how many texts I've used?

From the main waitlist page on the website, click the Usage option on the lower left. There you'll see a chart of your usage for the month. Use the menu in the upper right to switch to a yearly view. US/Canada subscribers can go to the Account page to see exactly how many texts have been used from the bundled texts for the current billing cycle. Clicking the Info bubble will show the next text refresh date. 

If you have multiple locations, go to the My Places page first to choose a location, then follow the steps above.