Spent 8 years pruning at the collar until a guy in Syracuse pointed at my cuts
I was doing a big sugar maple removal job in Syracuse back in April and the homeowner's neighbor, an old retired arborist, watched me work for 20 minutes and then walked over. He pointed at my pruning cuts from a job I did two years prior and showed me the tree never sealed over, just kept pushing sap and rot. I had been cutting too far from the branch collar my whole career, leaving stubs that the tree couldn't close. Anyone else get humbled by a random bystander who knows more than you do?
Cutting at the collar is not some magic fix either. I have seen plenty of trees with perfect collar cuts still rot out because the real problem was soil compaction or the tree was already stressed before anyone touched it. Blaming your whole career on stub length after one guy's opinion seems like a stretch, your mileage may vary though.