Can you advise at what mileage the timing chain and gears should be replaced to prevent the chain eventually skipping a tooth?
If and when you need to do any significant engine rebuilding, then replace the chain and sprockets. Short of that just let it go until you have a problem, excessive noise or that skipped tooth you mentioned.
Uncle Turbo Has it right. I changed mine on my chevy at a round 250,000 because I had leaking timing cover seal. It sill looked good for wear. A set was cheap to me at the time and I right there anyway.
Don’t confuse the timing chain on your motor with the timing belt used on many motors (mostly 4’s) these days. The chains are designed to run for a very long time, with very little or no maintenance.
It’ll get noisy before it does anything else.
For years the 302 Ford V-8 was notorious for jumping time between 60,000 and 80.000 with a manual transmission and between 110,000 and 130,000 with an automatic. That was when equipped with the segmented chain and sawdust cam gear. Later models used roller chains which were virtually a lifetime system. Check the specs on your engine. If it has a roller chain it will likely outlast the rest of the car.