Yes, I think it's a scientific fact that we cease to smell (that is, our brain ceases to take note of) what's around us constantly. Which makes sense from an evolutionary perspective -- we need to adapt to our environment, yet be alert to any unusual smells, as they might indicate a threat.
On vacation recently, I wore one scent for three days in a row, and by day three I could barely make it out. Isn't this why so many of us fragrance junkies change scent during the day? To reset the ambiance, and the nose.