How sharp do you want? You can cut hanging hairs, but not after any real use of the knife. I power-strop on a belt sander with Surgi-Sharp's leathers and Hand American's pastes, but getting that sharp an edge is really more for vanity than practicality. There's a small improvement in edge durability with the polish that stropping provides, but the biggest benefit is for straightening a folded-over edge after use. Even a polished steel mangles the edge a bit, while a strop works much better.