I own a Dewalt planer but not that one.
I got a tiny nick in one blade disappointingly early on but they are reversible, so I just flipped it over. Eventually, I sharpened them. I can't really say if I felt they dullened quickly or not as it is my first set of blades. Nothing to compare to.
My advice would be to buy some oversized Japanese water stones & angle guide and sharpen them yourself. A good set of stones doesn't take long to pay for themselves compared to buying blades. Also pretty much required for maintaining chisels and hand planer blades.
Kind of fun too. There is something strangely satisfying about creating a mirror finish on your now deadly sharp chisel.
