When to replace a chain?

[Jacobsroodt]

On my bicycles it is easy to see if the chain needs replacement. Use a chain checker tool.
But how do you know when to replace the chain on your bike? Yes, I know you can pull the chain backwards on the rear sprocket and look at tooth wear, but how do you really know?

I replaced a chain on a BMW F800GS on 31K km. The chain on my 2013 F800GS has done 18K km, with some movement observed when pulling the chain back from the rear sprocket - still some 13K km to go, compared to the previous chain. What are the measurables, and how?

 

[Jacobsroodt]

 

[Chopper]

 

[Bundu]

 

[Slainte Mhaith]

 

[Slainte Mhaith]

 

[Bundu]

 

[subie]

 

[Carnivore]

 

[Ratt]

 

[Smuggy]

 

[Ratt]

 

[ZA]

 

[GSBoland]

 

[subie]

 

[chopperpilot]

 

[Woestynhond]

 

[Jacobsroodt]

 

[Jacobsroodt]

 

[BFG]