Heater and radiator hoses aren't designed to last forever. They should be, but they just aren't. If yours are bulging, cracking or distorted, they're nearing the end of their effective life. Squeeze each one: if it's become either brittle or too soft, put it on the 'replace' list.
Avoid the embarrassment (oh yeah - and the inconvenience) of being stranded by the side of the road for something as simple as a blown hose. Also - consider replacing the clamps too, with smooth ABA style clamps instead of the more common cheese grater style.
