radiator hoses

I have a 93 APV with the 3.1 and heavy duty cooling system with the engine oil cooler, rear heat and A/C, and multiple fans on the radiator. The radiator hoses are all original. The hoses say Hi-Temperature on them. A GM mechanic friend told me that these hoses are special high temp heavy duty and should never need replacing. I'm concerned that these are 18 year old hoses. Should I replace them? The van just turned 75,000 miles.

Thanks!