If you're just looking at storefronts, how do you know what's viable and what isn't without making assumptions? Looking at real estate turnover tells you somet

If you're just looking at storefronts, how do you know what's viable and what isn't without making assumptions? Looking at real estate turnover tells you something about the location - and what businesses are appropriate for it - but doesn't tell you much about the viability of any particular business model.