Yes, as has been mentioned, it's the feel of the primer as it goes in the case. Wheher you seat the primers by one of the devices for that purpose, or if you seat with the press, you have to lean to feel how much pressure it takes to seat a primer in a good case. If a primer goes in easier than normal, it's a judgement call, do you keep it or throw it away? I sometimes push the questionable primer out, and try it again. I err on the side of safety on this. However, I have very, very few cases that I have to discard because of this, in spite of the fact I often load certain rifles and calibres heavier than what is shown in modern loading books.
While we're on the subject, the normal way a case wears out, is the developement of lengthwise cracks in the neck. This comes about from the constant sizing down, then expanding of the neck, during loading. There is no danger in these cracks. They are usually noticed after resizing, and the case will be discarded, as it has reached the end of its useful life.
Sometimes an insipient crack will not be noticed until it's found the bullet seats much easier than normal. If the loads are to be shot for an insignificant use, I go ahead, keep the cartridge and fire it. That will open up the crack, for sure.