What make/model brush stand are you using? I just got a Omega 10049 and its too big for every stand I have! Thanks in advance!I performed an experiment a few weeks ago to address this issue using three of my boar brushes. I used a Semogue Owners Club, Semogue 1305, and an Omega 10049 as test subjects.
I weighed each brush using a digital scale prior to beginning the experiment. After my normal shave routine, I thoroughly rinsed the brush and placed the brush bristles down in a stand. I weighed each brush after 24, 48, and 72 hours. In each case, the brushes returned to their original dry weight (within tolerances of the scale) in 72 hours so I saw no reason to continue.
These results are specific to my home environment. The brush was placed on a counter with sufficient air flow. There were no open windows or direct sunlight. The air conditioner thermostat was set to 74 degrees Fahrenheit.
I hope this helps.