Hi Smelmechiz,
That cutter sprocket will certain go for another round in my opinion.
As far as chains are concerned, just push the chain around it's sprocket starting from one end and see if it feels tight and snug at the other end of the teeth available on the sprocket, if there's some longitudinal slack or it doesn't fit absolutely spot on as you stretch it around, then it's time to change it on these slow running drive trains.
Cheers,
BB.
