Even with minimal occasions when I need to unscrew either the blade or lever cap on my wood planes, the brass screw head is getting beat up because of using either improperly sized or poorly fitted screw driver heads. Now I just use a proper thickness sized washer and file it down to a square tip. The remaining washer material is more than sufficient to exert the needed twist for tightening or loosening. Additionally, the washer hole is a great way to keep retain other differently sized washers on the same chain.