I ran into this same issue. The most useful additional cases, I think: "every Nth week" (or month) "every week on these days" (Tuesday and Thursday, for instance), "every month on these days" (Mth and Nth of the month, or Mth Fooday and Nth Barday of the month). I'd say it makes the most sense to combine these cases in the UI. In the following mockup, "text" represents a label, {text} represents a control, and other text represents a description. First line: "Every" {1,2,3,...} {weeks,months}, Second line for weeks: "on" {M T W Th F S Su} (allowing multiple selections, highlighting selected days) Second line for months: "day of" {month,week} {1,2,3,4,...,31} or {Nth} {M T W Th F S Su} [add] For months, each line would only take one day of the month or one day of week, and the add button would make another line.