Beyond 0.025"? I set them every few sharpenings, or if I have to take a lot off to repair a cutter or something. I dunno - the chain pulls fine in less hard stuff, and I'm worried it would be too much load then (it's only 46cc).
Right. Don't randomly hack metal off the depth gauges, to take them below .025" I tried that ONCE, with a well-used chain fortunately. The chain acted like it hit arresting gear, stress-testing crank. I'll never do that again.
One thing I really like about Granberg filing guide is the ability to precisely set depth gauges. Dial has a "bump" for each .010".
Once depth gauges are too low, you can't add on. You done did the pooch.