I had my 1988 Toyota Celica in for a lube, oil and filter change, and the mechanic said that I needed lower ball joints. I asked what was wrong with them and he said that they were worn out and loose.
I didn't really trust him so I declined to have them replaced. The mechanic responded by telling me that it could get dangerous if one breaks. Should I worry about this, and are ball joints a safety issue?
Worn ball joints can lead to a dangerous situation if not replaced. The lower ball joints are major parts of the front suspension that must hold up to an enormous amount of force. Their job is to twist and pivot with the up and down, and side to side movement of the suspension while supporting a large portion of the vehicle's weight -- in addition to the G-forces involved when braking, accelerating or cutting a turn. When a ball joint does break you can lose a wheel, along with control of the vehicle.
Bring your car into another shop and get a second opinion on the condition of the front suspension. If the ball joints are condemned once again, replace them. I'm sure the technician will gladly show you the excessive play that warrants the repair.
If the ball joints are confirmed to be in good condition then don't worry about it, and stay away from the questionable mechanic down the road.
Don't forget to always follow up with a front end alignment after the replacement of any significant suspension part.