This is what happened with this particular chair. The problem this chair had initially was that the wood of the entire chair shrunk, but not the wood of the seat. So all the seams holding the seat up were separating. The chair should have been taken apart, glued back together so that it would be tight and sturdy, then the seat re-attached. But instead, whomever tried to fix this chair did so by adding pieces of wood all over the place, putting in nails and screws of all sizes and they even used some 'L' brackets to try and achieve stability! This poor chair was a mess! I have taken a picture of all the extra things that were added to try and make this chair stable, It looks like they used half the hardware store!
Now this chair is going to need even more fixing than it would have before. We will need to fill all those holes made by screws and nails, Touchup all the holes to make them 'disappear' and then do the repairs that should have happened in the first place.
I write this post as a word of caution to you all. There is a right way and a wrong way to fix your furniture, if you don't know which is which, don't try fixing it yourself! Have a professional do it, or at least bring it to us, so we can explain how it should be done. You will save yourself quite the headache in the long run!