Answer 1: We are afraid that we cannot set the general lifetime, since the lifetime of the hose heavily depends on using conditions and using environments.
If you find the following features, we strongly recommend that it is time to replace into a new hose.

…Tear, Scratches, swelling, crack, curve, deformation, and exposure of reinforced yarns due to abrasion. The bursting of inner layer and/or outer layers of the hoses, hardening, dramatic change in color, and leaking fluids.