Over sized speedos?

[Torchwatch]

Oversize Speedos were more a thing when swimmers wore nylon swimsuits prior to Lycra being available.
As said above oversized nylon Speedos would give little or no support and a swim jockstrap might have to be worn after puberty
Lycra Speedos rapidly became popular among swimmers as they gave more support, holding everything firmly and they gave less resistance when swimming in water allowing the swimmer to go faster.
Buying Lycra Speedos a size too large to allow for growth because of the stretch in the fabric will still fit firmly but allow the swimmer to grow to fit the Speedos properly and to continue wearing them until they are a size too small.
The problem with wearing old overstretched Speedos is that the bottom of the suit loses it's elastane and starts to hang down to your knees.
Parents, at the point that your son's Speedos are hanging down half way to his knees please buy him a new pair, you've had your money's worth out of them. Leaving damp Speedos rolled up in a towel or bunging them in an electric tumble drier will kill the elastane in the swimsuit. Care for your Speedos and they'll care for you!