gdaladdo levels

[Travis Kirstine GIS Tech]

Hi everyone,
I was hoping someone could provide some clarification regarding the GDAL
utility gdaladdo and the usage of the levels.  I know the basics of gdaladdo
but how does the level function actually work?  For example I have a 1m
resolution floating point DEM tif image that covers 250km2 and I would like
to use gdaladdo to increase performance.  Ideally the image will be view at
scales ranging from 1:100,000 to 1:500 and I would like to keep the cell
resolution at 1m at the higher scale levels.  Any info would be a great
help.
Thanks for your time
Travis