Most GPS units are accurate to within about 30 feet (15 feet or so with a good WAAS lock)(and yes I know these numbers are not exact, I'm just estimating), so theoretically if the cache owner placed the cache with his/her GPS unit and only had a 30 foot accuracy, and then you come along with your GPS that only has 30 foot accuracy. Technically you could be 60 feet away from the cache. But most likely 30-45 feet is about what I have seen, in all the caches I have found (yeah i know its not that many). Only 1 cache was way off from the coordinates, and it required a second visit, with 2 additional GPS units to help triangulate its location. Even with 3 GPS units, the location provided by the CO as compared to those looking for the cache, seemed to be off by about 20 feet.