Superstition plagues almost every sport in some way or another. Baseball players have a certain way they have to get set (my girlfriend told me about a girl on her team who would rub her hand in the dirt and then lick it before every single pitch). In golf, some players refuse to start a hole with anything other than an odd numbered club. In hockey, players often tap the goalie on his/her pads with their sticks before the game for good luck.
In BJJ, one of the most common superstitions is quite a bit grosser. Many people refuse to wash their belt (and sometimes even their gi) for fear of washing the magical power out of it.
I can’t stress enough how nasty this is. Quirky superstitions are one thing, but foregoing basic hygiene out of superstitious belief is simply too far. Think about how much sweat, skin, and blood gets soaked into your belt (not to mention your gi) from just a single night of training. Often, my belt and gi are soaking wet when I finish a class, most of which probably isn’t from me.
Incidentally, know what else can soak into unwashed equipment?
Or how about:
You’re welcome for the biology lesson folks. Respect the health of your training partners – wash your equipment regularly. Ideally, your gi should be washed after every class. Your belt probably doesn’t need to be washed after every training session, but at least wash it every week if you train multiple times.
Besides, if you’re worried about magically losing your jiu jitsu prowess by washing your belt, just think about how much training you’ll actually miss out on when you’re off the mats for a month with a staph infection.