People always post NM in my area, but I've never seen a NA. I guess it depends on the situation, but I logged a NM yesterday because the cache had DNFs for over a year, with no finds in-between, and the logs were pretty descriptive of how everyone searched hard.. so I just want the CO to confirm that the cache is still there. If I searched and couldn't find it, but someone else found it earlier, I wouldn't mark it... I probably wouldn't mark it if a few people before me couldn't find it and neither could I. It seems to be a case-by-case scenario... I wouldn't use it too frequently, but there are some caches that do indeed need maintenance.