Are they easy to see from the street? This isn't just a consideration for dinner party guests — first responders need to be able to spot the numbers right away in an emergency. Some cities even have codes that dictate how large numbers must be; check whether this is the case where you live.Step outside and study your house from the street to check how well the numbers show up. Is the font clear and readable? Do you need a bigger size or more visual weight? If your home is set back from the curb, numbers on a mailbox or post close to the road will probably work better than numbers hung above the door.