Over the past 15+ years more and more people have started running. Having worked in the outdoor and running industry particularly in footwear for over 20 years, no one wants to be a bigger shoe size. Runners will run more miles, gain more elevation, have a high heart rate, go for a faster time, but the aversion to getting a larger sized shoe NO WAY!
It amazes me to hear about all the foot issues runners can come up with, high this or narrow that, numb over here, different lacing patterns, tingling toes, runners knots, wide fore foot, black toe nails, blisters... You get the idea.
After a detailed foot measurement, alignment check, and volume measurement I bring out a few pairs of shoes. "Wow these feel great!" this is usually followed by "what size are these?" Then follows, "I've never worn this size before".
Your feet change. Gravity is on and walking and running take a beating on your feet. Especially in shoes that do not fit well or are not designed to support the foot.
Do yourself a favor, have your feet measured. Pay attention to the arch measurement. This is your foot size, which corresponded to a shoe size.
Keeping feet happy and faces smiling!