How long does it take to diagnose suspension issues?

I have a 2007 honda jazz. Last week my car was making a creaking noise when turning the wheel. Took it to my mechanic who listend to it and said could be the suspension arm and to bring it in the next day. When I drove it there the noise had stopped so I told him.

He basically kept the car all day and told me every time he tries its not making the sound and he can't really see what's wrong. He said he suspects it is the ball joint but to bring it back if the noise comes back.

Today the noise came back and also a slight knocking noise on occasion. Spoke to mechanic and he said bring it in the morning and he will get it up on the ramp and have a look.

I don't get it, I'm no mechanic but I would have thought if the ball joint is worn wouldn't it have been obvious when he had it last week all day? Clearly there is something wrong so how could it be that he couldn't see anything?