i knew mine was blow out, because when i put my car on the lift, the strut didn't stay connected to the car, just kinda fell out lol.

look for deep cracks in the rubber, or holes, ect. sometimes it'll look fine from where you can see it, but be bad where you cant see it.

We always order the mounts when ever we do them, just in case one is bad, we've got them. Sometimes use them, sometimes dont. But you have to have them all the way off inorder to do a proper inspection.