Between five different bikes its been at least since 2004.....

Not Tuffys, no "punture resistant tubes, no slime, and several sets of extremely lightweight tires (i.e., Maxxis 310s, etc.), but the tire pressure is checked daily before I ride. And I'm still doing between 3k-5k miles a years minimum, but I have no idea how far each bike has gone except that three of the bikes have never had flats since they were built.

I think a lot of flats are caused by not really paying enough attention to what is in front of you. I've had several friend on road bikes ride right through broken glass on the road because they were talking to each other. In most cases I will surrender my own spare tube and swap them out because I hate to have to wait while they fumble with tire tools. I draw the line at pumping up the fixed wheel though.....