How do I tell if I need wide shoes?

I'm curious, how does one determine if they require wider shoes? Is there a specific measurement or guideline to follow? Are there any signs or symptoms that may indicate a need for wider footwear? Perhaps there are certain types of activities or lifestyles that make wide shoes more suitable? I'd appreciate any insights you may have on this topic, as I'm seeking to ensure the comfort and fit of my footwear choices.