If it is a local cache we'll look until it is not fun, or have to go to work, or wash my hair. We post a DNF if we gave it a real try, as we appreciate the DNFs posted that help us monitor our own caches. Vacations are another story. We use (gasp!) paper printouts without comments that may be a month or more old. Some caches are gone by then. I looked for one in Washington that was near our camp (.13 mile) and was frustrated by the clues and comments that told me I was standing right next to a 1 star cache. Got home to read that the owner had removed it for cleaning during that weekend.
Just move on!