When I spend time with very athletic women, I sometimes ask them when, and how often they weigh themselves. I feel like it has psychological significance. And the two most fit women I know say never. Maybe once a year at their annual physical. Our Yoga teacher said that somewhere like a women's college cafeteria there had been a sign saying, "Don't weigh you self-esteem." So the answer of whether and how we weigh ourselves is gonna vary for everyone but that's a nice koan.
PS: Off-Topic: Another nice koan my dad says about skiing is, "Never take the last run."