A PS to this post.
After changing a chain, a good wear comparison is to hold the new and old chain
from the end on it's side view and see how well the other end supports itself. The worn chain will droop a few inches compared to
one in good condition. This is due to wear in the links that you can't really notice trying to measure the chains. This will really show up if the chain has been cleaned of the remaining oil. If there is
little difference between the two when they are changed and the complaint is chain rattle, this is an indication that the
tensioner should be changed.