While you're buying
those new mounts, presumably "rubber" since the exotic silicone types are kinda hard to find or afford, remember that rubber doesn't like petrochemicals. The motor
mounts, the hoses, anything "rubber" should get a rubdown with ArmorAll every once in a while, it really does prevent a lot of deterioration. Or a dusting of talc, plain talcum powder, which apparently "fills" the surface of the rubber well enough to substantially stop oxidation and chemical attacks. It makes an incredible difference.