It really depends on who you are asking. Some woodworkers say that the saw shouldn’t be more than an eighth of an inch above the cutting surface. Others think that the blade should be as height as the bottom of its gullet, which is the spacing between the blade’s teeth. In my opinion, it is all about the rake angle, although some heights do help with kickback more than others in specific scenarios. That varies from manufacturer to manufacturer, though, so make sure you check that user’s manual when you get a brand new saw.