I'm glad to hear that! Calendar systems don't store all the individual dates of a repeating event. We just store the "formula". Then for every day that we display, we check to see if the formula gets triggered. As a result, the display gets slower as you add more repeating dates, but then there are tricks to make it faster. Caching is done, calculating the potential first/last dates a formula could trigger results in not needing to do the calculations for dates outside that range, etc.