You're driving along watching the mailbox numbers, looking for the next stop. Suddenly, house after house has no numbers displayed whatsoever. Then the next number you see is way ahead of what you were looking for. Alternatively, you have a lane with a bunch of mailboxes at the front. But when you get to the end, you find a toilet of houses and trailers with not a single number. What do you do about this? I usually try to knock on the door of the house I suspect and ask. Not always effective. But if I have one more follow-up because of numberless houses, I swear I will no-such-number their stuff every day until I see a number.