I too am a newbie with the same concern. So far, if I have that problem, I log it as did not find, then watch the cache and if someone else finds it after me, I at least know it wasn't muggled. Then I try it again with a fresh perspective and sometimes it justs pops out where it should be. I must be a masochist because I love the feeling I get when I slap my head and go "Duh - of course thats where it is".