A groom needs two shirts for his wedding, ideally in the same design. This is because incase there are any mishaps at the wedding where a drink, food, or make up stain comes on to the shirt. It will also come in handy if the weather is warm or the event is long and the groom is sweating. Most grooms tend to feel hot in their suits due to the spotlights being on them. So having an additional shirt can come in handy.