For example just recently I got a call from one of my flyers. The woman said she was in Spearwood. I realized I hadn't done that area for months. And a person I've been doing this for intermittently for ages mentioned that she got a call from someone a couple of years after I'd distributed them. (She knew this because of what he referred to when he called.)
So if you get a flyer campaign done it's best to not expect them to come back straightaway. That's easier said than done, particularly if you've put out quite a few.
I believe that this impossibility of knowing when you'll get a response is what causes some people to feel that the method just doesn't work.
Say a business commissions a run of a couple of thousand. Only one call comes in over the following week, then nothing for weeks on end. After a month the business owner concludes that this is all he's going to get. He thinks: "I got just one call from two thousand. No good. Won't try that again!"
But over the next couple of months after that another four calls trickle in. That then means the ultimate response rate was closer to one in four hundred. That's not bad -- particularly if it was in an area that had never done before.
Unfortunately this new evidence doesn't make him reappraise his initial conclusion. Determined to be decisive, he made up his mind for good early on. So he never uses the method again. That's an unfortunate outcome and one to be avoided if possible.