When does the axle seal need to be replaced in a car?(00)

When does the axle seal need to be replaced in a car?(00)

Image gallery: Axel Leak

When does the axle seal need to be replaced in a car? How To Fix A Leaking Rear Axle (Replace Axle Seals) Is it Safe to Drive with a Leaking Axle Seal? YourMechanic Advice