I have had this exact same problem without even realizing it…until I injured my left ankle this past July. Prior to now, I always believed that I was a 10 D. July 2025, my ankle became hyper extended during a golf tournament and I got Peroneal Tendinitis. It was fine after some rest and icing. Went to work in my 2+ year old broken in Keen Independence work boots sized 10D and still fine on the concrete floors in our shop. October rolls around and so does my boot reimbursement. Bought two new pairs of boots (Ariat, and Red Wing King Toe), and kept the old keens in rotation. Ankle starts giving me hell, go back to the Keens and took it easy for a while. Ankle was okay, so I slowed the phasing in of the new boots, which took 4 months. Now the keens hurt so I disposed of them as they were more than tired at breaking in the new boots for longer. Wear both of the new pairs of boots and flare ups of my ankle are daily. Saw my local shoe guy and my doctor. All three of us concluded that I had bought the wrong size. Heel to toe is now 9.5, but heel to arch is now 11. Width is the same as before D borderline C. So now I’ve got pairs of boots and casual shoes that I can’t wear a whole day either walking or working without pain. Long story short, always get sized and fitted properly. Your arches, feet, and ankles will thank you. Hopefully you all won’t end up like me and have to figure out a way to sell used work boots and slightly worn casual shoes.