Do I really need to replace the whole axle if the cv boot is leaking for $500?

What is your question?

I don't know what a "CV Boot" is so I'm flying blind on this and have to take their word that it's leaking.They say the best thing to do is replace the whole axle assembly at a cost of $500..never had any problem with it before but I've had it since 95!Time to replace it?