Per Stormin Mormon:
His recollection was that in something less than an hour, one's sense of
smell adapts to a constant odor and the odor is no longer noticed.


I observed that while cleaning grease trap
at McDonalds.

Now that I am thinking about it, there was a lady where I worked (nice
lady...) that discovered perfume late in life.

At first it was about right... then it got stronger and stronger until
she reeked of the stuff from across a room.

The prevailing theory was that people get used to the smell and then
apply more and more of the stuff until they get the smell they are
accustomed to.... and nobody warned her about that.
--
Pete Cresswell