I have been doing plumbing for 40 years. I think shark bites came out in the last 10 years or so. So far I have only seen one of them fail. It failed on a system that was not properly freeze protected. Being the weakest point in the system, the shark bite fitting failed before anything else in that system, as it froze.
Due to the fact that the system relies on two principles which seem to run contrary to all other plumbing principles, I tend to still be somewhat suspicious of them . Here are the two principles that seem to be a bit weak to me:
1. Relying on a simple rubber O-ring to make it permanent pressure seal. While rubber does often seem to last for 20 to 30 years, I seriously doubt that these O-rings will last beyond 30 years.
2. Often relying on a "contact point" between two dissimilar metals for structural integrity. The stainless steel barbs in shark bite fittings, which most typically dig into copper pipes, would seem to me to create a "weak point" for future failure.
My best guess is that they will probably start to have systemwide failures after 15 to 30 years. I just don't like to gamble like that with the systems I install.
My opinion here, and about $2.00 will generally get you a good cup of coffee, for whatever it may or may not be worth.
Thanks,
Scott Perry