ORIGINAL: rslstft
Wayne22 is probably right about the earlier version of the H-9 floats. I had a set on my Cub that split along the bottom after about 50-60 landings. The 2nd set I have on now seem to be a bit more sturdy. No reason they shouldn't last you quite a while as long as you don't slam them into the water. I have more than 250 flights on the 2nd set with usually several touch and goes on each flight and they are holding up just fine.
Fiberglass beefs up the bottoms nicely