The next time you shop for a swimsuit for your child, resist buying one that's a size too big, hoping your child will grow into it. You're wasting your money, says Matt Zimmer, promotions director of TYR in Huntington Beach, California. In fact, swimmers of all ages get more wear out of a suit that's as tight as a second skin. A snug suit retains its shape and chlorine-resistance better than one that twists around the body in the water. A suit that fits right should be taut and smooth across the torso, and it should pass the strap test: Slip a thumb under the top of one strap and lift. The strap shouldn't reach your earlobe.