I sharpen mine about twice a week, while they're on the machine. Three minutes each time.
I've been spanked for sharing my cowboy method (A.Lopa, Ekka) and maybe it
is a little crude, raw and shoot-from-the-hip, but my knives stay truly sharp and pleasant, always. After ~ 6 months I flip em over to the new side and start over. When side 2 is worn, a new set goes on and the old ones get sent back to the manufacturer for pro sharpening.
Mine's a small chipper, very few guys use 6" machines, so I may be off the chart with nothing much of value to offer the group.
I'll just be polite and step out
(Very interested to know how others do it, though.)