it wasn't, but maybe it was a bit over the top.
when i rode loose bearing headsets, i probably cleaned them once every three months or so. sometimes more if i felt one of my bikes was turning sluggishly, but i don't think i ever had to once a month-- not sure why i said that.
but i will add that even a freshly packed headset doesn't rotate as smoothly as a well made sealed bearing set (in my experience), maintenece frequency aside.