I mow a maintained lawn, somewhat less than one acre about 40 times a season. No trees, leaves or sticks.
Maybe your sandy soil is eating away at the blades?
Attached is a picture of the blades I've been using since I got the tractor. It will be 24 years in February.
I've always just dressed the blades by hand with a file. I think there is a hardened area on the cutting edge and when the blades are sharpened past that point they are junk.
I looked into mulching blades at one time but it doesn't seem they are available for my deck.
I'm guessing I got my money's worth out of my blades.
