Mine was an Ace Hardware that had a sharpening service. I started taking them there to be sharpened. One day, decided a specific tree (within distance of hitting house should it fall the wrong direction) needed taken down. Started sawing and the tree settled, pinching my bar.
Fine... I have an extra bar & chain this very circumstance. Got tools, removed powerhead from bar, put other bar and freshly sharpened chain.... and the freshly sharpened chain would cut melted butter. They neglected or forgot to file the rakers. Chain was useless. Wife's cousin next door....saw was down. Called brother in law, he said he'd come over "later" to see if he could help.
I decided to run into town, get replacements and come back to finish....meanwhile, I had the first cut of my wedge cut meaning the tree was cut something like 1/3 into the face with my bar sticking out.
As it happened, by the time I returned, my brother in law had arrived. He brought his saw and had dropped the tree before I returned.
I've never had anyone else sharpen my blades since then..... AND (if you've seen my comments elsewhere) this is another reason why I like the idea now of just digging part of the root ball and using my backhoe to push the tree over.