A guide on how to check controll armS and how to replace them would be awesome ( now i want to check mine ).
For future reference: They are very easy to check.
1. You need to unload them by getting the wheel next to the joint you need to check off the ground.
2. By either using just your strength but ideally some sort of lever/pry bar try to move the control arm up and down+side to side. Making sure to check if the control arm side of the ball joint is moving.
3. If you can feel any notching and if there is any sort of free play in the actual ball joint it is time to replace them.
If the boot is split, it greatly reduces the life span of the ball joint by allowing dirt and contaminants to wear out the nylon socket.
It only ever seems to happen at low speeds while turning sharply, which probably isn't a bad thing!