I am not a fan of frequent scrubbing; it slows things down a lot. So, I set it up monthly on the 31st. It runs 7 times a year, one day of which is New Year’s Eve. Another of which frequently falls on Memorial Day weekend.
As long as we are suggesting features, Why not allow specific days. In January I could schedule scrubbing on Presidents Day, Memorial Day, 4th of July, Labor Day, Thanksgiving, Christmas, and maybe New Years Day.
If QNAP can find an Open source global calendar with local holidays, setting our location could display official holidays.
Then depending on the type of NAS usage, we could choose the global scrubbing frequency and include/exclude certain kinds of dates, to suit home or business usages.