check the rollers on the chain and see if they are cone shaped if not too bad you can switch sides to get some additional wear and also flip the sprockets over at the same time
When you are out of adjustment on the adjusting screw (l shaped arm that bolt goes through is resting up against the jam nut) they are worn out. I have taken the jam nut out to get a few more acres to finish the season (for a little more adjustment) but you run the risk of wearing the pins so thin that the chain might break. John