I'm not an expert on Model A's, as I just recently built mine, but my 61 Chevy pickup still has the radiator hoses that I put on it when I started driving it on high school in 1995.
I drive it almost daily in the spring summer and fall, and it has a pressurized radiator, unlike a model A, that is non pressurized.
I check them every time I change the oil, they are still in good shape, not too brittle, not too soft and squishy. I figure I will run them till they either get brittle or squishy, then I will replace them.