My DIllon trimmer did about 30,000 before it chipped the carbide. It really screws up the brass pretty bad when it chips. But your mileage may vary.
PS: there are 3 sides to the carbide, so in theory you could do 90k before having to buy one..
I have under 5k and my blade chipped right on the corner, two sides are our of commission. And your right, it destroys the brass, makes it look like someone deburred the case with a buck knife. It could have been a faulty blade, or one of my ugly brothers that have not got a clue.