Cam chain

[limax2]

Checking the remaining tensioner clicks was the key thing that made me take the plunge and change the chain.  So I'd say check that before anything.

Just to add a bit of info. If you want to check the tensioner clicks, don't forget to release the large nut on the end to release the spring pressure before removing the tensioner body. Otherwise the spring will push the tensioner out as you remove the body. Likewise when putting the tensioner back the large nut is fitted last.