It does seem excessive. I replace my chain once a season and I ride between 2500 and 3000 miles a year, at least for the past 3 years. On the other hand, I am not really good about cleaning my bike (I know). However, I don't ride in the rain or seem to be in an area where there's lots of crap on the road. I look at the tires and pump them every time I ride and I have had one flat in eight years (not counting the one where I ran over a nail on a century and decimated the tire, not just the tube). My husband does all the maintenance and I keep a look out for anything that seems weird with my bike.
I would not use a patched tube. Just my opinion. We keep a supply at home and buy them a bunch at a time, from the evil internet source. I always have 2 in my bag.