Spent my first 4 seasons pruning flush to the trunk and I still cringe thinking about it
I was at a job site in Raleigh about 6 years back and the homeowner came out and asked why her maples looked like they had open sores on the sides. I walked over and saw the flush cuts I had made, all sealed over all wrong, and it hit me that every pruning job I'd ever done probably looked the same way. The old timer I worked under always said to cut close so it looks clean, and I never once questioned it, just ran with it for 4 seasons. Now I spend extra time finding the branch collar on every single cut, even on little stuff, and it adds maybe 10 minutes to a trim. What finally got you to change how you cut, was it a client or a foreman or just seeing the damage?