Cars can suck

My husband's car has been having some problems recently. I looked into roadside assistance for him, just in case something happens when he's on the road. But it tends to be pretty pricey. We can't decide if it's worth getting it or if we'd be better off waiting until something happens to call someone. I know that THAT can be expensive. But how much money would we 'waste' on a roadside assistance plan that we might not even use?