I have had relatively good luck in terms of not getting busted in the big woods with mine not brushed in and I leave mine out for 3 months at a time, but they are in the shade and heavy cover for much of it so no chance for sun bleaching.

I might also add sent control and wind are much more important on the ground.

Here is a good article I did a search on and finally found:

http://www.bowhunting.com/fieldjournal/fieldjournal_detail.aspx?nID=416