I buy replacement blades. I'm pretty good at blade sharpening, but it just isn't worth my time to sit and toil with them when I can purchase replacements pretty cheap. I keep the old ones for practice, and I'll often spray them with a quick coating of flo orange paint..... no mistaking them then. Just gotta keep it a super light coat or you'll change up stuff.

There are some styrophom targets you can shoot into that will actually sharpen the blades as they hit. Those big blocks that Northern Tool and Equipment has heavy stuff shipped in on will do it. They are free if you can find them.... and they will stop any arrow off any bow pretty quick.