If a bike chain is used to 1% stretch, is will be one full link longer than a new having the same number of links, but if you lay a new chain beside it, the ends that match up would not be the same as the old chain and it couldn't be joined. You can easily see the mismatch increase as you get to the end of the chain. The new chain would be 1/2 inch shorter, but have the same number of links and the ends can be joined. Counting the number of links is never needed.