Comment 2 for bug 1284564

While it doesn't fix all use cases, you can probably shorten "sun, mon, tue, wed, thur, fri, sat" to "daily" and "mon, tue, wed, thur, fri" to "weekdays". "sat, sun" could be "weekends" and any other combination could be "day-day" e.g. "mon-wed". Clearly it's breakable with "sun, tue, thu, sat". It's probably also breakable in non-En languages too. Just a suggestion :)