If you have flatted that many times in a month, it could simply be a foreign object in your tire. I had a tire, with what seemed to be a dust-sized piece of glass in the rubber, and I kept flatting! I needed a new tire...

And there are ways to change the rear tube without taking the wheel off the bike... heh... I have done it so many times it is sad. My hands just get so dirty touching the rear derailleur when I am cranky!

Anyway, tires last a long long time, unless something makes them unhappy (like an itsy piece of glass or wire). It takes a long while or a trainer fly wheel to wear them out significantly.
http://sheldonbrown.com/tires.html#replacement

Don't sweat it. And getting more confident with changing flats (even if you leave the wheel on like I do for the rear), will make you so much more relaxed. I like to ride alone...

As for puncture resistance... those tires make changing tubes an absolute PITA! ouchie to my fingers and tire irons! i'd rather change tubes slightly more frequently than deal with those. I inflate before every ride anyway... 115-120psi...