Having three kids from 2-13 and two crazy boxers we have had numerous broken glasses and mugs over the years. I ran into silipint cups and thought, eh, why not see how they work. We loved the first two I bought right off the bat. We've since ordered several others in different colors and styles. They've already been put to the test with falls. Still not liking the spills but love the bounce!! No more worrying about things like did I get all the broken glass cleaned up, was anyone hurt, oh drat that was a gift mug I can't replace. These are a worthy investment.