How to tell when the blade should be sharpened?

[Freshman]

What is a good test to tell if a blade should be sharpened? Cutting hair, paper, I don't what to over or under sharpen.

[Sword and Shield]

Just take a sheet of newspaper and cut a long slit in the paper. Any drag or pulls in the paper signify that the knife could use a touchup. If it cuts cleanly, the knife is plenty sharp.

Keepin' it real...real sharp, that is.

[vampyrewolf]

I use my knife daily, so any noticable difference in proformance gets a touchup. I carry a DoubleStuff from spyderco in my backpack...

We all start with 10 fingers. Those with Spydies have 9 to spare, Still need a thumb. Good thing I still have 8 to spare...

[RYAN]

Hey Freshman. Use caution if you try this method. I use what is called the "Samarai Hair Test." Lightly scrape the blade's edge along the hair on the back head. If the blade "catches" easily on your hair, it has a good edge. If the blade slides down your hair easily, it is time for you to resharpen it.

[thorin hammer]

The way I tell if my knife is dull is to hold the edge of the blade under a bright light and look for reflection. If there is any reflection then you can see the edge, time to resharpen or at least touch up. Hope this helps.

Some laws permit, what honor dose not.