As it turns out, your foot size can change over the course of your life. Who knew? If you've been wearing the same shoe size for years, it's worth double-checking that they still fit properly so that you don't screw up your feet and require months of recovery hahaha fml

• When you have running or athletic shoes on, you should have about a thumb's worth of space between your longest toe and the tip of the shoe
• When you put all your weight on your foot, the upper part of the shoe shouldn't bulge out on the sides. If it does, you need either a wider size or a size up
• Your feet expand throughout the day, so that's the best time to check
• Your feet are slightly different sizes, so check both
• You can add arch support with insoles if needed

Those are the basics, but there's more info here: https://www.asics.com/nz/en-nz/mk/choosing-the-right-running-shoe/finding-the-right-fit

Also, if anyone needs some men's 10.5 shoes, I have a bunch for you