If I'm using a paper I've never tried before, I'll do a straight print on that to get a sense of how fast or slow the paper is under the enlarger, but otherwise I rarely do straight black and white prints before going on to lith prints. I've found that I have a pretty good eye for what will make a good lith print, so I don't usually bother with the intermediate step. I also never bother with test strips, except in the few cases where a paper or image is giving me real problems and I need to see a variety of exposure times on one paper. That being said, if I can't get an image I like (or see the potential of getting better) within the first 3-5 prints, I usually put that neg away and try something else. On the otherhand, once I get a lith print the way I like it, I try to make as many as I can (at least 5) and consider them both final prints and/or possibilities for further toning trials.