I am at 35 hours and have yet to sharpen the blades and when i run my finger across them they are still fairly sharp. The cheaper blades I would sharpen every 2 to 3 days but the marbane oem blades hold the edge very good. They are even hard to sharpen they are so hard. I can sharpen the cheaper blades and the dedicated grinder takes meat off quickly. Set those down and try to sharpen the oem blades and it is slow to remove the metal because they are much harder. Something is goofy with mtmowers situation. I can get an entire seasons worth of sharpening out of even the cheap blades before they are too beat up and worn down to continue using them.
2013 Gravely 460Z 29EFI
2011 Gravely 36GR
2008 Gravely 160Z
2004 Gravely 34Z
1998 Lazer Z HP 48 (old faithful)