It's always better to have control of a knife you're using, sure, but everyone makes mistakes. And you shouldn't lose a perfectly good knife just because it sinks to the bottom of a lake or the shaft cracks on your tile floor. Is the solution bouncy knives? Sort of.
Spanish design company Baladéo made the "It Floats" pocket knife and keyring, $25 (£15 before shipping), so all of your important stuff will stay buoyant. It weighs less than 60 grammes and the shaft is made of cork to keep everything afloat. The knife is probably most useful for kayaking/fishing/hiking etc., but it's also kind of great looking. [Baladéo via Uncrate]