Just last week the shaft on my 8 iron broke between my hands under the grip as I started my downswing. The shaft went through the grip and into my index finger. I had to get 5 stitches.
I use Project X Rifle shafts (6.5) and they were only about 2 years old. I don't abuse my clubs but I do keep them garage .... maybe it was rust but it didn't look that bad.