This question is not a duplicate of either (1) Ice skating on a frozen lake -- how thick should the ice be?, which only asks how thick the ice should be; or (2) How to determine the thickness of ice?, which only asks how to determine how thick the ice is.
When I was a child, we skated on a couple of lakes in Connecticut. One day my father would declare that "It's safe now" and off we would go. No one ever fell through. He did not drill.
My question is: short of drilling, how do locals decide the ice on their lakes is safe for winter sports? I don't remember the criteria my father used, except on the larger lake the ice had to extend very close to the spill-way, which was in essence an artificial outlet stream. (We stayed away from that area.) If it was safe on the larger lake, it would be safe on the smaller lake.
Where I live (Northern VA), the only safe assumption is that the ice is never safe.
Clarification: If you think drilling is the only way to declare ice safe, in your area for your lakes, that would be a valid answer. But I am still more interested in how people can make the judgement without drilling.