The edge quit halfway through the board, so you blame the steel. Wrong alloy. Not hard enough. Should have bought the premium iron everyone keeps posting about.
Sometimes that's the problem. Usually it isn't.
An edge doesn't just "go dull." It fails in one of three specific ways, and the way it failed is the diagnosis. Learn to read it and you stop guessing.
The first is abrasion. The edge rounds over slowly and evenly. This is normal. It's what use looks like, and the only fix is the stones. Nothing went wrong.
The second is folding. The very tip rolls over, and it happens fast. That's plastic deformation, and it means your bevel was too low or your steel was too soft for the work. A steeper bevel fixes it. A harder iron won't hurt either.
The third is chipping. Little nicks at the apex, brittle fracture, usually right after you hit a knot or a patch of wild figure. That one wants a tougher steel, not a harder one. There's a difference, and run your iron too hard and you make chipping worse, not better.
Three deaths, three fixes. Mix them up and you spend money solving a problem you don't have.
Now the part that reorders the whole thing: in everyday hardwood work, the wood decides how fast you're back at the stones, not the steel. Silica content alone accounts for close to half the variation in wear rate. That's why teak is famous for eating edges. It isn't the density. It's the sand the tree grew up with.
Some species go further and corrode the iron chemically through their extractives, and no amount of hardness buys that back, because it isn't abrasion, it's chemistry. Western red cedar is the quiet one here. Soft, easy to plane, and it'll dull an O1 iron faster than the hardness numbers say it should.
So before you ask what steel to buy, ask what you're cutting. Edge-life advice that ignores the species is advice about the wrong variable.
And then there's the plane itself, which stops cutting before the tip is actually blunt.
Here's what's happening. Behind the edge there's a small clearance angle, a degree or two, that lets the iron ride up off the wood. As the bevel rounds back from honing and wear, that clearance shrinks toward zero. Once it crosses, the iron is rubbing its heel on the surface instead of slicing into it. The shaving compresses, heat builds, and the plane feels dead. The apex might still be fairly keen. You ran out of clearance, not sharpness.
That's why "how dull is the tip" is the wrong question when you're deciding whether to hone or regrind. The right question is how much clearance is left. A plane that's lost its clearance needs the bevel taken back, not another pass on the fine stone.
So the next time an edge gives out, read it before you reach for the catalog. Look at how it failed. Think about what you were cutting. And in a plane, ask where the clearance went. The steel matters least where most of us assume it matters most.