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Hellin Kay

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Has it been a few years since you've stepped on one of those metal foot measurers at the shoe store? Well, we're here to deliver some toe soul-crushing news: You might be wearing the wrong size---and it's likely too small.

According to experts, your feet can change size ever so slightly throughout your life, which could explain why you can no longer force your way into those perfect Manolos you snagged at a sample sale 10 years ago. Wearing shoes in an incorrect or outdated size can lead to painful problems like calluses and bunions, which will make those summer sandals look less appealing.

In general, the average shoe size has gone up two sizes since the 1970s, and designers and retailers are feeling the effects. Stuart Weitzman told The Wall Street Journalthat his company's average size used to be a 7, but has crept up to an 8, and he now makes shoes that go up to size 12 due to increased demand.

The only solution? Constant vigilance! Sizes vary widely between different brands, and even within the same brand, so it's something to be aware of when shopping. Yes, vanity sizing is even a thing with shoes, so shoppers who always pick the same size often don't get the best fit, experts note. If you're buying kicks online, order multiple sizes at once, and be sure to try them on late in the day when your feet are biggest.

And if you do discover that you've been a size 9 all along, you're not alone: Nearly half of women and one-third of men admitted to buying shoes that didn't fit correctly, according to a study by the U.K. College of Podiatry. Better stay on your toes, people!