When to replace ball joint?
 

I had my 2000 Disco Series 2 up on a lift at a mechanic the other day, and they said my ball joints should be replaced and quoted me a heft $1050. I have not heard any knocking, no vibration in the wheel, no drift down the highway... So I'm wondering what signs should I look for to replace them? Why replace them before I have issues? What would a person see that would indicate they need to be replaced? Thanks.

your mechanic should have showed you the issue. You can move the tire and see the ball joint move, over thousand to replace ?
Get a new mechanic

Here is how I tested mine below on a suggestion from Brian a member here
also just as a reference my local mechanic charged me $350 Canadian to replace ball joint I bought a moog ball joint from rock auto



Jack up front of vehicle so wheels are hanging about two inches off the ground, then rest axle housing on jack-stands (this helps eliminate movement of axle housing, while prying with prybar), get a long prybar and someone to either watch ball joint area or pry up for you, place prybar under the tire, then lift upward. You want to watch for independent movement of the ball joint and spindle knuckle, if you are seeing this (ball joint moving upward before whole assembly moves)...ball joint is bad. If the whole assembly moves as one...ball joints are okay. Now, ball joints can become dry inside and cause binding...without showing signs of unusual movement.

Grasping the tire front and back and wiggling would find hub, tie-rod, drag-link or sloppy gearbox issues.

How are the boots on your CV joints, if they are torn...you could have issues there. Bad CV joints will pop while turning if they are bad.

The info redwhitekat offered is correct. With the tire off the ground use any kind of pry bar you have or can adapt to the purpose to check for play in the joint when you try to lift the tire and wheel using the pry bar. But I don't see why jackstands are needed; just use your bottle jack and check one side at a time.

The chief mechanic at the best independent Rover shop here told me they've seen trucks go for years with shredded rubber boots but no play in the joints. That's been the case with my truck; shredded rubber boots with no indication of any problems with the joint. I check them with a pry bar regularly. The truck just turned 177,000 miles.

Ask your mechanic how he made his diagnosis and let us know how this turns out for you.

Prior posts are 100%. 178xxxmiles on my rig and I believe stock ball joints with non existent boots,(upper/lower/both sides) no play as well. Maybe parts changer guy at the shop was trying to entice you with torn boots, unless there actually is play.

X3.

180k+ and original ball joints. Boots have been gone for years, but no play.