Not that often really, unless I've been cutting against something hard, or I flatten the blade on something like an engine block.
For the most part if the angle is correct, not to thin for job being performed, other than occasional touch ups on a steel or a ceramic rod to realign the edge, resharpening shouldn't be needed.
I'm hard on my knives, harder than most I suppose, and I still sharpen them only once a month,( this is also probably due to fact that on any given day I probably carry about 3 or 4 EDC's).
Now short of being in Landscaping,(they happen to be harder on knives than me, digging in the dirt, cutting burlap around the rootballs, ect), or a chef,(and even those guys don't sharpen everyday, they steel their blades)there's no reason to sharpen every day.
As an afterthought if you find yourself constantly touching up your blades, maybe they were never completely sharp to start with.
Often when you sharpen a blade if the wire edge is not completely removed the edge may feel sharp but as you cut, the wire edge rolls over making the blade seem dull, or it acually breaks of leaving flat spots on the edge.
This alone counts for more resharpening, and over sharpening of most blades, afterwards I hear the complaints, "it was sharp but this cheap POS won't cut after 1 or 2 uses."
It come down to these few items really,
1) Proper Blade geometry
2) Proper secondary bevel for the thickness of the blade, and the intended purpose of the blade.
3) Last but not least proper edge maintenance
Sharpening is not magic, it's persistence, knowledge, and consistency.
This gives me an idea for a future thread, more to follow.
