Caps with no seams and fewer wrinkles are considerably more effective at decreasing friction. The less friction a swimmer experiences, the quicker he can swim. Because latex swim caps do not allow water to pass through them, they keep your hair drier. This means you can swim longer without getting wet. Latex is also antibacterial so wearing a cap will prevent any bacteria that may have been living on your head from being passed onto the pool floor or other swimmers. This is especially important if you have a young child who might not think to wash their hands after going to the bathroom near the pool side. Wearing a cap will help prevent any bacteria that may live on your head from being transferred to others. Swimming with a hat on is better than not having one at all. However, not every cap is created equal. A well-made swim cap will stay on your head better and be less likely to move around too much which allows you to swim longer without feeling self-conscious. If you have long hair, a swim cap with holes in it will let some of it hang down while keeping out water. This is helpful if you want to swim but don't want to get your hair wet. There are also plastic caps that look like real hair caps but only come in small sizes that will fit over even the longest hairs.