I never owned a variable speed router until about 8-10 years ago. I also sent all my router bits to be sharpened after each job I did while in business. Unfortunately, most of the sharpening companies here in Tucson at the time have all retired or moved to other locations. The sharpening services here don't do as good a job as the old guys. I'm not that busy as I'm supposed to be retired, so sanding out burn marks is okay, except for burns on Hickory.Isn't it also a function of the speed you run the router around? When I was making those curved legs on the hall table I found there was a sweet spot where I didn't get burning but not so fast I got tear out. Of course, staying in that sweet spot going around curves wasn't easy. Guess if it was easy everyone could make awesome furniture. My guitar coach runs his router wide open, but it's the speed he moves the router around the guitar that controls the tear out.
I did some experimenting with actually grinding my own bit about 5 years ago by getting a 6" grinder from Harbor Freight. The first thing I did was toss out the wheels supplied, and put on 4 different Lapidary discs with grits from 80 to 3000. Worked better than any I ever bought or sent sent out for sharpening. Did this mostly for the carbide turning tools I use. .............. Nubs