I finally wore out a brew kettle. About 12 years ago I bought a really cheap 4 gallon aluminum pot to use when I started extract brewing. After switching to all grain a few months later, I still used that pot a lot for heating water for preheating the mash tun, decoctions, etc., along with some occasional regular cooking. I beat the shit out of this pot over the years. Finally today, I see that I now have a pinhole leak in the bottom in between all the dents and wrinkles in the bottom.
For those who believe that they should only use stainless because it lasts longer, pay attention. It took me 12 years (200+ batches) to wear out a really cheap aluminum pot while abusing the piss out of it. A quality aluminum pot with good care should last you a lifetime.
I still won't throw this thing out. It will hold crushed grain just fine.
BN Army // 13th Mountain Division 
