On oil. I have bars that are 40+ years old that saw 20+ years of commercial service, then me cutting firewood and milling with them for another 20 years. Most of our saws, in the 70's had automatic oilers, but they all had thumb pumps too. Dad would give anyone heck if they weren't constantly pumping. Always use a full tank of oil per tank of fuel. Back then I never heard of "Bar Oil". We just used the cheapest 10W30 oil we could get, by the case, at KMart. I still use 10W30 unless I catch a good sale. To put in perspective how much my saws still get used, I mix in 5 gallon batches, and use about 5 gallons a month. By the 80's we bought enough saws, pretty much all Homelites, that other dealers started sending us flyers on their products. Then I remember reading one manufacturers theory on using thick oil that would cling to the bar and lubricate longer, and an others claim that thin oil was better because it flew off the end of the bar, carrying heat off the the bar keeping it cooler. Both theories had a pile of scientific research to prove their side. We kept using 10W30, and now I have 40 year old bars, still in service. I adjust the chain so you can pick it up with 2 fingers, and the drivers come to the top of the bar groove, but not sagging off the bottom. I would rather run it a little loose than tight.
On filing, I still free hand with a chunk of an Oak stick stuck on the file for a handle. I rotate the file after every stroke, and every third or fourth stroke I tap the file across the chain to clean out the filings. I think the files last longer that way. A sharp chain will create less heat and aid in longer bar life. When you have to start leaning on the saw to cut you are creating a lot of heat. I can buck up an Oak log and hold the bar in bare hands when done. If the bar is so hot you can't touch it, you are not using enough oil, your chain is dull, or too tight. That bar won't last long.
Sharp chain, lots of oil, long bar life, Joe.