Timing change?

Is there a recommend mileage to change the timing chain. I have 47564 miles and unknown previous of pass owner maintenance.

Any advise?

I don't think, but the manual talks about checking for timing chain stretch through this little window in the timing chain cover.

If I remember correctly, the manual isn't very clear on what to look for.
Maybe when you can move the chain to the right far enough to meet the pointer, then it's bad?

https://i.imgur.com/KbjL8INl.jpg