[Tom P]

Rubber inside the hose rots and the braid hides the cracks. I used to get hose free off a friend that worked at a helicopter place. They change the hoses on a scheduled basis.
But five years seems to be all that is safe unless you use Teflon lines. I got a 25 ft roll of 1/2" steel line and -8 fittings from Summit and ran two 12 ft lines from the pump to the regulator up front and a return.