Rough guideline?
Get used to "your saw" with a sharp chain. Look, listen & feel. How's it sound, the chips look long & big,
You have to hang on when you pull the trigger, it wants to pull hard. Cutter tips look & fell sharp.
Performance: cutting time has dropped off on similar sized rounds. If easy to pull the saw out of the cut when running, getting dull.
Sound: RPM stays high when in the meat of the cut where before it would get that low growl & just eat wood.
Many here can be out cutting & hear another saw running & know it has a chain problem from the sound
Eyeball: Look at the chips it's spitting out now & then, saw dust is not good, should be spitting out chips.
wood chips stack up fast with a sharp chain,
Chips not saw dust.
Tips of the teeth are hard to see, no shiny spots usually mean it's sharp. See shiny tips, time to sharpen.
Smoke or steam off the cut or chain means it's getting hot, which many times means dull.
Best way is monitor all 3. Know what each is like when the chain is new & sharp.
Will get to be a habit, you'll notice it getting higher rpm, you'll feel how the sharp saw wants to pull into the cut & when dull it don't. Seeing saw dust is a sure sign it's dull.
After a while you won't even think about it, You'll know you have a dull chain. You'll decide if you want to finish up with a dull chain ,
or have enough left to cut that it'll be faster if you sharpen or change it out
1/2 cord or so from tree to rounds, a touch up with a file never hurts. Justifies a well earned break too.
