I just skimmed the post and rd35 was the first post that addressed why the chain was getting dull in the first place. If any one else said it, sorry I missed it. My brother in law told me our local saw dealer had a bad batch of chains, they were all dull out of the box. I told him the chains were fine, it was driver error,he was hitting the dirt. He said he wasn’t. I came over and he had a log cut up on the lawn,and every cut went through and cut a strip of grass. I pointed at them and said that’s why your chain is dull. He said, oh,that little bit doesn’t hurt. YES IT DOES. If you just nick the ground, it’s exactly like taking your sharpest butcher knife and bumping the edge on a bench grinder. If you have dirt packed in the bark take a hatchet, grubbing hoe, and clean it out. You don’t have to clean the whole log, just the cuts. My BIL asked how he could cut all the way through without hitting the dirt? He has a Kubota with a loader on it. I said cut most of the way and roll the log over. Or, put several small logs/limbs next to it and roll the log on them. Don’t have a loader? Get a can’t hook. Take a shovel and dig a hole under the end and use a floor jack and jack it up and slide stuff under it. I’m starting a job today, a tornado went through and knocked down about 30 24-32” Oaks, I have to haul all of the wood out. I’ll be cutting in 8’ logs, and the small stuff into firewood length. I plan on getting 10 trees a day. My saws will still be sharp when I’m done, unless I hit steel in a tree.
I’ve been doing this over 50 years and hand file all of my chains, no guides or gadgets, just by eye. I recommend you start with a guide and practice.
Also, if you are clearing an area, or cutting down several trees, leave a 2’ high stump, then cut off all the stumps last. If you are flush cutting stumps the down side of the chain will get into dirt and dull faster than the up side, and the next thing you know your cuts will look like bananas.