Can you run a scratchy piston

[Noobi06]

A lot of people say you should replace the piston when its scratchy.
Others say as long as the piston ring is in good shape, you can run a very scrathy piston.
What is right? I know the more hours on a piston, the more risk of it cracking or breaking cause other stuff to get destroyed such as the cylinder.
Also, if number 2 is correct, doesnt that mean I can run the same piston for hundreds of hours and just replace the ring every now and then.