I had some great luck earlier this year when I created a special effect just before St. Patrick's day: a Shamrock poofer. I sold a great many of them that day, but of course very few since then. Occasionally an Irishman seems to buy one. At the time I was pleased with the high sales on that one day, but disappointed with sales afterwards – even to the point of believing the product was not really a success.
However, I got to thinking: if this product is successful only on one day a year, why not have a series of products that would be successful on different days? After all, once built, a product requires little attention and you can pile up products to cover a lot of special occasion days through out the year.
Looking at the calendar, it occurred to me that the national holiday for both Canada and the US was coming soon. So I created a special poofer for each country and placed them both for sale just before the important dates (Check out the picture of WarmSpirit Williams and I trying them out). Sure enough, I am selling lots of them.
This seems to be a moral of the story: a product that works only on a few days is not successful, but many products that each work on different days is successful.