Depends on what you want to know
and when you want to know it.Hi Sam. .01 miles is the smallest increment our alarm will set to so our adjustments are in roughly 60 foot units. If you've got, say 100 feet of rode out and you have it set at .01 it will go off if you just swing around your anchor arc. You may want to know that when you're sleeping or otherwise not paying attention just to make sure you're still stuck. On the other hand, if you're feeling secure you may not need the darn thing going off each time you swing so you might set it at .02 or .03 miles (roughly 120 or 180 feet respectively.) That way it'll only go off if you're actually dragging.The other thing to be aware of is the decision to either turn it on when the anchor drops (which will tell you if you're moving beyond the diameter of your anchoring circle) or to set it when you're backing it down (in case you want it to tell you if you're swinging from that side of the circle as mentioned above.)Anyway, happy anchoring!