My wife has a new Samsung Galaxy S5. I have an almost 2 year old Droid Razr Maxx. c:geo can have both of us right on top of the cache coordinates (according to the app), yet we can be standing 20-30 meters apart. Or even if we are standing still, we can be moving 10m here, 15m over there, 20m back to where we were a minute ago. Finally, on mine at least, it may have me on Maui instead of Molokai (50 miles away), or Bakersfield instead of the Sierra National Forest (100 miles away). At other times, one or both of ours are dead on within a meter.