I was told when i bought my mower " don't bother with sharpening your blade just come in and buy a new one"
I sharpened mine for the first time at the beginning of the Season (on my second season) and it makes a difference. It needed it, I miss picking up some of the fir tree cones and the odd bits of branch which tends to nick and dull the blade on my lawn. I sharpened it while on the mower because I have not been able to get it off the machine. The factory torque on the nut must have been turned up...lol. If someone has trick to getting the blade off the mower please share.