I was the exact opposite, I was getting numerous flats on the MTB, but went to one every year when I switched to my current hybrid bike. The type of tires I was running probably was a factor in the number of flats that I was having on each bike. A month ago, I just installed some kevlar strips to the inside of my tires, and now I'm looking to decrease my flat occurences to one every two years. I still carry an extra tube, tube sealant, tools, and a frame mounted tire pump for good karma and to help a stranded cyclist.